Beginning Of Spring Research Articles

Glycymeris bimaculata (Poli, 1795) — A new sclerochronological archive for the Mediterranean?

Glycymeris bimaculata is one of the largest (up to ~115mm) bivalves in the Mediterranean Sea, yet there is a paucity of information about the biology, ecology and growth of the species. Maximum longevity, growth and periodicity of internal shell growth line formation were assessed in individuals collected from Pag Bay in the Adriatic Sea. We validated annual periodicity of line formation using stable isotope analysis of shell calcium carbonate to construct standardized growth indices (SGIs) in live collected specimens obtained in 2008 and 2012 and developed a statistically robust master chronology from the growth increment series to explore shell growth responses to environmental indices. The estimated age of 55 shells (shell length 49.1 to 109.5mm) ranged from 6 to 57years and shell growth is described by the von Bertalanffy growth equation: Lt=90.85−(e−0.10(t+3.13)). The dark growth lines visible in acetate peel replicates of polished and etched shell cross-sections were deposited annually at the beginning of spring. Growth increment data for the period between 1991 and 2007, derived from 9 individuals (age between 17 and 34years), were used in the construction of a master chronology. The SGIs had pronounced inter-annual variability with the period between 1997 and 1999 characterized by slower growth, the period between 2000 and 2005 by moderate growth, while the widest growth increments were deposited in 2006 and 2007. Differences in growth between these periods were related to differences in surface seawater temperatures and salinity.

The number of emergency department visits for psychiatric emergencies is strongly associated with mean temperature and humidity variations. Results of a nine year survey

Several disorders, such as renal colics, stroke, atrial fibrillation and others, are epidemiologically associated with seasonality and microclimatic variations. Although evidence is still limited, an association between psychiatric emergencies and seasonality has also been previously described. In order to elucidate the possible association between weather and incidence of psychiatric emergencies in a country with temperate climate, we analyzed the influence of day by day climate changes on the number of visits for psychiatric emergencies in an urban emergency department (ED) of northern Italy. All ED visits for psychiatric emergencies were retrieved from the hospital database from 2002 to 2010. The total number of ED visits was 725,812 throughout the study period, 11,786 of which for emergency psychiatric problems. We found a strong seasonal distribution of emergency psychiatric visits, peaking in summer and at the beginning of spring. The linear regression analysis showed a strong positive association between number of daily emergency psychiatric visits and mean daily air temperature (R=0.82; P<0.001), and an inverse association with mean daily air humidity (R=-0.52; P<0.001). These findings suggest that psychiatric disorders follow a significant seasonal variation, so that it may be advisable to strengthen psychiatric emergency services during the hottest months.

Seasonal changes and endocrine regulation of pejerrey (Odontesthes bonariensis) oogenesis in the wild

The goal of this study was to evaluate the essential components controlling the brain–pituitary–gonad axis during pejerrey (Odontesthes bonariensis) oogenesis in the wild. Ovarian developmental stages from vitellogenesis up to ovulation were associated with increasing day length and water temperatures below 21°C (winter and beginning of spring). Gonadal regression was observed when water temperature exceeded this value or when photoperiod decreased. Most females were arrested at primary growth stage during summer (high temperature) or at cortical alveoli stage between autumn and beginning of winter (short photoperiod). Plasma E2 and transcript levels of fshr, cyp19a1b and cyp19a1a increased during vitellogenesis, while fshb remained high at all vitellogenic stages. A significant correlation between plasma sex steroids (T and E2) and cyp19a1b as well as lhcgr transcript levels was observed during vitellogenesis, suggesting a steroid positive feedback. Gnrh-I, Gth subunits and lhcgr transcript levels increased significantly during late vitellogenesis and final maturation. Present results suggest that pejerrey vitellogenesis is controlled by Fsh/Fshr, stimulating gonadal aromatase and estradiol synthesis. Moreover, the increase of testosterone and estradiol during final vitellogenesis could induce coordinately the functioning of the Gnrh/Lh system (perhaps through brain P450 aromatase stimulation and brain estradiol increase) and the gonadal Lhcgr synthesis to promote the final maturation of oocytes. All these stimulation mechanisms of gonadal development would be possible only under permissive environmental conditions.

Assessing climate change impacts on Upper Grande River Basin hydrology, Southeast Brazil

ABSTRACTBrazilian electric power is mostly based on hydraulics sources through hydropower plant reservoirs that are fed by rivers located in Southeast Brazil. Possible changes in climate can affect the energy supply of the country. The objective of this work is to assess the possible changes in the hydrology of the Upper Grande River Basin (UGRB) under a future climate change scenario, using the Lavras Simulation of Hydrology (LASH) model forced by the outputs of the Eta model, a regional climate model, which was driven by HadCM3 A1B scenario for three time slices in the period between 2011 and 2099. Owing to the surface heterogeneity of the region, the hydrologic model was previously calibrated for four watersheds of the UGRB, which are located in its headwater region and evaluated against observational time series of the present climate period, 1961–1990. In the first future time slice, 2011–2040, the results showed a small reduction in the annual run‐off, but for the other time slices, the trend changed to strong increase in most of the watersheds. The water budget in the region calculated from the Eta model agreed with the run‐off trends, as water excess reduced in the first time slice and gradually increased towards the end of the century. The run‐off components showed intraseasonal variability. The reduction of rains in the end of winter, the dry period in the region, and in the beginning of spring, may cause a change in the dynamics of the groundwater recharge, affecting the base flow, which can extend and intensify the flow recession period, and therefore affect the availability of water resources. On the other hand, the increase of rains during the summer, the rainy season of the region, caused an increase of the direct surface run‐off, which can modify the flood regimes of the rivers in the region.

Climate and environments during Marine Isotope Stage 11 in the central Iberian Peninsula: the herpetofaunal assemblage from the Acheulean site of Áridos-1, Madrid

The interglacial episodes of the Quaternary Period are currently the focus of a great deal of attention within the scientific community, primarily because they can help us to understand how the climate of the current interglacial may have evolved without human intervention and to assess the impact of these climate changes on ecological systems. In the central Iberian Peninsula, the archaeological site of Áridos-1 (Arganda, Madrid), with numeric dates of 379.7 ± 45 ka obtained by AAR for the upper part of the sedimentological unit of Arganda I, in combination with the evolved state of the small mammals, has been chronologically attributed to Marine Isotope Stage (MIS) 11. Given the diversified faunal assemblages delivered by the 1976 excavations, Áridos-1 is probably one of the best terrestrial candidates for an understanding of the climatic and environmental conditions that prevailed in central Spain during the MIS 11 interglacial. In consequence, the fossil amphibians and squamate reptiles stored in the collections of the Museo Arqueológico Nacional of Madrid have been newly described and quantified in order to apply the mutual climatic range and habitat weighting methods for estimating quantitative data. The Mediterranean climate is shown to have been warmer and wetter than today in central Spain during MIS 11, with the mean annual temperature 1.7 °C higher and mean annual precipitation 223.9 mm higher than at present. The monthly climatic reconstruction shows differences in the distribution of precipitation over the course of the year, with more abundant precipitation during the winter months, at the beginning of spring and at the end of fall (from October to March) and less precipitation than today during the summer months and at the end of spring (from May to August), suggesting stronger rainfall seasonality between winter and summer than currently occurs. Such climate reconstruction is consistent with other European MIS 11 paleoclimatic records. The paleoenvironmental reconstruction based on the herpetofaunal assemblage suggests a patchy landscape with a large representation of dry meadows, scrubland and rocky habitats together with well-evidenced aquatic habitats. Such open environments during a warm and humid forestal period are seen to be connected with the location of the site in a large river valley, where open vegetation would have been partly initiated and certainly maintained by the grazing, browsing, trampling and tree-felling activities of large mammals.

Study of tributary inflows in Lake Iseo with a rotating physical model

The influence of Coriolis force on the currents of large lakes is well acknowledged; very few contributions, however, investigate this aspect in medium-size lakes where its relevance could be questionable. In order to study the area of influence of the two major tributary rivers in Lake Iseo, a rotating vertically distorted physical model of the northern part of this lake was prepared and used, respecting both Froude and Rossby similarity. The model has a horizontal length scale factor of 8000 and a vertical scale factor of 500 and was used both in homogeneous and in thermally stratified conditions. We explored the pattern of water circulation in front of the entrance mouth for different hydrologic scenarios at the beginning of spring and in summer. We neglected the influence of winds. The primary purposes of the model were twofold: i) to increase our level of knowledge of the hydrodynamics of Lake Iseo by verifying the occurrence of dynamical effects related to the Earth’s rotation on the plume of the two tributaries that enter the northern part of the lake and ii) to identify the areas of the lake that can be directly influenced by the tributaries’ waters, in order to provide guidance on water quality monitoring in zones of relevant environmental and touristic value. The results of the physical model confirm the relevant role played by the Coriolis force in the northern part of the lake. Under ordinary flow conditions, the model shows a systematic deflection of the inflowing waters towards the western shore of the lake. The inflow triggers a clockwise gyre within the Lovere bay, to the West of the inflow, and a slow counter-clockwise gyre, to the East of the inflow, that returns water towards the river mouth along the eastern shore. For discharges with higher return period, when only the contribution by Oglio River is relevant, the effect of the Earth’s rotation weakens in the entrance zone and the plume has a more rectilinear pattern, whilst in the far field the current driven by the inflows keeps moving along the western shore. On the basis of these results one could expect that the north-western part of the lake between Castro and Lovere, although not aligned with the tributaries’ axes, is more sensitive to accumulation effects related to river-borne pollution. The results obtained with the physical model are critically compared with data obtained from different sources: the trajectory of a lagrangian drogue; a map of reflectivity data from the lake floor; a map of water turbidity at the intrusion depth. The findings are also confirmed by the results of a 3D numerical model of the lake .

&lt;b&gt; Initial height of pasture deferred and utilized in winter and tillering dynamics of signal grass during the following spring &lt;/b&gt;

Tillering dynamics during regrowth in the spring (September to December 2009) on signal grass (Brachiaria decumbens cv. Basilisk) pastures deferred in the beginning of April 2009 is evaluated. Four pasture heights were evaluated at the beginning of deferment (10, 20, 30 and 40 cm). The experimental design consisted of completely randomized blocks with two replications. Rise in pasture height at the beginning of deferment decreased the appearance rate, increased the mortality rate and reduced the survival rate, the balance between appearance and mortality and the stability index of the tiller population at the beginning of the spring. Pastures deferred at initial height of 30 and 40 cm presented relatively stable tiller appearance rate between the beginning and end of spring. However, these pastures presented greater mortality rate, lower survival rate, lower balance between appearance and mortality and lower stability index of the tiller population at the beginning of spring when compared to rates at the end of spring. Pastures managed with shorter initial heights (10 and 20 cm) provided more tissue renewal in the subsequent growth season after their utilization in the winter.

Statistical modelling of the main features of the Artemisia pollen season in Wrocław, Poland, during the 2002–2011 time period

The aim of this article is to present statistical forecasting models concerning the dynamics of Artemisia pollen seasons in Wroclaw, including the start and end, the date of maximum pollen concentration and seasonal pollen index (SPI). For statistical evaluation, use was made of aerobiological and meteorological data from the last 10 years (2002–2011). Based on this data, agroclimatic indicators, i.e. crop heat units (CHUs), were determined for various averaging periods. The beginning of the Artemisia pollen season in the studied time period, on average, took place on 23 June. Its length usually varied between 26 and 45 days, and maximum daily concentrations occurred between 31 July and 18 August. It was found that the beginning of the pollen season depends, above all, on the values of CHUs and photothermal unit (PTU) (p < 0.05) in the period from March to June, for various thermal thresholds. The date of maximum daily concentration correlates with sunshine duration, PTU and air temperature for June and July (p < 0.05). On the other hand, SPI is connected with thermal variables, i.e. average, maximum and minimum air temperatures and CHUs and heliothermal unit (HTU) for July (p < 0.05) and the beginning of spring. Based on the correlation analysis and the chosen variables, regression models for the beginning date of Artemisia pollen season and SPI were prepared, which were then verified by using leave-one-out cross-validation. A better fit between modelled and actual values was found for the analysis concerning the season start date than for the SPI.

Ensayo clínico aleatorio para evaluar la eficacia de una intervención educativa desarrollada en atención primaria sobre asmáticos adultos

ObjectiveTo assess the effect of an educational intervention on asthma control and quality of life. DesignA randomised clinical trial of patients with asthma, with an intervention group (IG) and a control (GC). Asthma control and quality of life was measured in both groups at baseline and every three months for one a year. Blinding was only possible in the collection and analysis of data. LocationTwo urban Primary Care Health Centres ParticipantsA total of 163 patients aged 18 to 55 years were included: 84 were assigned to the IG and 79 to the CG. The follow-up was completed by 104 patients (GI: 55 and GC 49). InterventionGI: Three educational sessions in small interactive groups. The first session was at the beginning of spring, the second 15 days later, and the third 6 months later, to recall the knowledge. Main measurementsAsthma control level and quality of life using ACT(Asthma Control Test) and the AQLQ (Asthma Quality of life Questionnaire). ResultsIn the third month, statistically significant differences were detected in the percentage of patients with good control [(P=.0002), 75% in the GI, and 48.5% in the GC, Relative Risk (RR)=1.6 [1.2 to 2.1], Number Needed to Treat (NNT)=3.8 [2.4 to 9.4], and an improvement in levels of quality of life from baseline (P=.005), RR=2.3 [1.3 to 4.1], NNT: 4.3 [2.6 to 12.4]. No differences were detected in the remaining sessions. ConclusionsThese interventions are effective in improving the control and quality of life in short-term, which can guide us in choosing the best time to do it.

Floating Treatment Wetland influences on the fate of metals in road runoff retention ponds

A field trial comparing the fate of metals in two parallel stormwater retention ponds, one of which was retrofitted with a Floating Treatment Wetland (FTW), was carried out near Auckland, New Zealand. Results suggest that the FTW increased metal accumulation in the pond sediment especially in summer due to lower sediment Eh, more anoxic water column, neutral pH and greater source of organic matter (OM) induced by the FTW. These factors combined with higher temperature enhanced metal sorption onto OM, flocculation of particulate pollutants, metal sulphide formation and reduced OM degradation and thus limited release of metals. Unlike Zn, Cu speciation in the pond sediment was relatively unchanged under various sediment Eh conditions due to its strong binding property with sulphide and OM. Occasional moderate metal release was detected from the FTW pond sediment likely due to aerobic OM degradation at the beginning of spring and/or hydroxides reduction when sediments became reduced later in the season. No release was noticed from the conventional pond sediment likely due to biosorption and/or uptake by algae which developed in the conventional pond and settled on the bottom sediment. Direct uptake by the plants of the FTW and sorption onto root plaques are not thought to be significant removal pathways. Nevertheless roots play a major role in trapping particulate pollutants, eventually sloughing off to settle on the bottom of the pond, and provide an adequate substrate for bacterial development due to release of organic compounds which are both essential for dissolved metal sorption and metal sulphide formation.

Job the Afflicted

Job (Ayyûb) is one of God's prophets cited in the Koran. His name, experiences and patience are cited proverbially and as a narrative account in the daily lives of Arabs and Moslems. A seasonal folk ritual performed in Egypt at the beginning of Spring mimics certain aspects of the Job belief-cycle thus reinforcing its foundations. This ritual is presumed to restore health and prevent skin maladies. The account is found on other cultural levels, including parareligious stories in older literary works, and on oral folk levels, where a ballad (narrative folksong) describes the tribulations Job's wife Ruth withstood. The ballad circulates in the form of a pamphlet and as a song or hymn performed by wandering “maddâhîn (praisers)” who travel on foot in the countryside and city quarters expecting donations from listeners. In the early 1950s the Job ballad was presented to middle-class Egyptians on the national radio as a play. Its emotional impact proved to be profound.

Determination of Fe, Zn and Cu in ambient air by Combining pre-concentration Methods and FAAS

The main sources of human exposure to trace metals for non-occupationally exposed individualsare inhalation and ingestion. Because the absorption rates of the metals by inhalation are significantly higher (up to 50-60%) than those by ingestion (between 3% and 10%), determination of trace metals in ambient air samples is of special interest. The main purpose of this study was to determine Fe, Zn and Cu in ambient air by combining pre-concentration methods and flame atomic absorption spectrophotometer (FAAS). In the pre-concentration step, adsorption reagents including 4-(2-pyridyl-azo) Resorcinol (PAR)-loaded XAD-7, thioureasulphonamide polymeric resin and cupferron-activated carbon were used sequentially. Under the optimum conditions, seasonal distributions of Fe, Zn and Cu concentrations in ambient air of Elazig City, Turkey, were determined. Concentrations of Fe, Zn and Cu were found to be in the ranges of 154-416, 101-323 and 12-75 ng/m3, respectively. High Zn levels determined in March and April can be attributed to the burning of coal at the beginning of spring.

Dynamics of yield components and stevioside production in Stevia rebaudiana grown under different planting times, plant stands and harvest regime

Stevia rebaudiana (Bertoni) Bertoni is well known because of its accumulation of the sweet-tasting ent-kaurene diterpeneoid glycoside, which tastes about 300 times as sweet as sucrose. Although stevioside is one of the most abundant and best analyzed, more than 30 additional steviol glycosides so far have been identified and described. Stevioside concentration in the leaves is known to vary widely, depending on the growing conditions and agricultural practices. The present study aimed to examine the feasibility of growing Stevia as an open-field crop in Israel. In order to determine the agricultural practices required for optimizing Stevia biomass production and stevioside yield, effects of planting and harvest times upon plant development, biomass yield components, and stevioside content were examined. The optimal planting season, manifested in intensive plant development and maximal plant biomass yield, was at the beginning of spring, i.e., mid-March to early April. A minimal stand of 10 plants/m2 was found more favorable than lower stands of 6, 8, or 10 plants/m2′‘. The optimal harvesting time, with the highest stevioside yield of about 30g/m2 was at the beginning of September, prior to flowering initiation. Moreover, harvesting at this time yielded increased leaf biomass, highly suitable for commercial stevioside extraction. Thus, Stevia rebaudiana offers substantial potential for introduction as a commercial agricultural crop for stevioside production in Israel.

A quantitative assessment of the effects of formal sun protection education on photosensitive patients

To quantitatively assess the effect of formal sun protection education on sun exposure habits and quality of life in photosensitive patients. Patients with chronic actinic dermatitis (CAD) or polymorphous light eruption (PLE) were randomized to either the intervention or the control group. General advice about sun protection and broad-spectrum sunscreen were provided to all participants. The intervention group was given two additional intensive sun protection instruction classes at the beginning of spring and then in summer. At baseline and 12 months, each participant completed interviews that included a questionnaire about sun protection behaviors and a modified Dermatology Life Quality Index (DLQI) questionnaire. In the intervention group, after the first intensive sun protection instruction, all aspects of sun exposure habits were significantly improved from baseline (P < 0.01). At study's end, there had been no significant change in sun exposure habits in the control group compared with baseline, whereas sun exposure habits in the intervention group significantly improved (P < 0.01). After two intensive sun protection training sessions, the modified DLQI significantly decreased in the intervention group compared with baseline (P < 0.001), while no change was observed in the control group. Formal sun protection education improved sun exposure and protection behaviors as well as quality of life in photosensitive patients.

Comparative dynamics of pelagic and benthic micro-algae in a coastal ecosystem

Together with phytoplankton, microphytobenthos (MPB) play an important role in the overall food web structure of coastal ecosystems by regulating nutrient fluxes, oxygen concentration and sediment stability in the ecosystem. Although there are many studies on phytoplankton, MPB dynamics in the subtidal zone are largely unknown. In this study, we carried out a whole-year survey to investigate the seasonal dynamics of phytoplankton and MPB biomass simultaneously in relation to the environmental physico–chemical parameters. We show that phytoplankton and MPB do not follow the same dynamics with MPB being the first to increase in the season. It constitutes a large energy input to the ecosystem from the beginning of spring (with 60% of the total biomass until April). The system then moves from a system dominated by benthic biomass in early spring to a system where the pelagic biomass dominates. Among resources that MPB and phytoplankton have to share, light seems to trigger the MPB bloom as soon as maximum bottom PAR is reached, i.e. one month earlier than the phytoplankton bloom in the water column. With regard to nutrients, the lack of phosphorus can be put forward to explain the decline of MPB biomass at the beginning of April, whereas the phytoplankton decline in the first week of May coincides to silicic acid deficiency. Dissolved inorganic nitrogen then becomes potentially limiting in the water column until the end of October. Competition with macroalgae at the bottom and grazing were also considered as being possible factors for the disparate course of phytoplankton and MPB dynamics. Further investigations are needed to give a more detailed picture on the interactions and feedback loops between MPB and phytoplankton. However, although benthic-pelagic relationships are complex, this study indicates the need to integrate such fundamental coupling to a thorough understanding of ecosystem dynamics and functions.

Forage accumulation in brachiaria grass under continuous grazing with single or variable height during the seasons of the year

The objective of this study was to evaluate grazing management strategies of Brachiaria decumbens cv. Basilisk managed with different heights under continuous grazing with cattle. Two grazing management strategies were evaluated: maintenance of pasture with an average height of 25 cm throughout the experimental period and maintenance of pasture on the average of 15 cm in height during winter, up to 25 cm from the beginning of spring. The split-plot scheme and the randomized block design with four replications were adopted. The grazing management strategies corresponded to the primary factor, while the seasons (winter, spring and summer) corresponded to secondary factor. The reduction of the average sward height to 15 cm in the winter resulted, when compared with pasture maintained at 25 cm, in overall higher growth rates (95 kg/ha.day DM) and leaf blade (66.1 kg/ha.day DM), as well as higher rates of total accumulation (81.5 kg/ha.day DM) and leaf blade (52.6 kg/ha.day DM). The accumulated forage production (from winter to summer) was higher in the pasture lowered to 15 cm in winter (25.6 t/ha DM) compared with that managed with an average height of 25 cm (22.2 t/ha DM). Regarding the seasons of the year, in the winter, there were lower rates of overall growth (6.4 kg/ha.day DM), leaf blade (5.6 kg/ha.day DM) and pseudostem (0.8 kg/ha.day DM), and also lower total (-6.6 kg/ha.day DM) and leaf blade (-7.5 kg/ha.day DM) accumulation rates. In the spring there was a higher rate of leaf senescence (22.4 kg/ha.day DM). The accumulation of forage is incremented when the pasture of B. decumbens is lowered to 15 cm during the winter, and in the spring and summer, its average height is increased to 25 cm.

A cellular automaton model of Schistosoma japonicum infection

Due to the life cycle complexity of Schistosoma japonicum and the characteristics of schistosomias is immuno-epidemiology, it is very challenging to give a group of certain rules and thus describe the transmission dynamics of S. japonicum with modelling approaches. Most existing epidemiological models for schistosomias is based on differential equations only track average worm burden without taking into account the individual variations, thus bear limitations on individual infection status monitoring and interpretation. In this paper, an improved stochastic model based on cellular automaton (I-SjCA, briefly) has been introduced to describe the transmission dynamics of human schistosomiasis japonica in an endemic area in China. This model reflects the process of the pathogen invasion from exposure to worm development and worm death when the infection is cleared; it also incorporates seasonality of infection, and stochastic behaviour of each individual in the study field. We show that based on the data collected from the 706 study participants, the model-predicted prevalence and intensity of S. japonicum in the 2nd year of investigation is comparable with the observation. Furthermore, we illustrate the use of model for evaluating possible control strategies for schistosomiasis in context of simulated prevalence and individual infection probability. The simulation results suggest that chemotherapy should cover no less than 85% of the S. japonicum infected population to guarantee an effective drug control program, and the best time for annual chemotherapy with praziquantel is the beginning of spring in the endemic area. Our findings indicate that I-SjCA model based on the cellular automaton can effectively simulate the transmission process. It is anticipated that our cellular automaton transmission model can serve as a tool for understanding schistosomiasis transmission dynamics and thus be conductive to build an effective control program.

Seasonal Reproductive Activity of Domestic Queens (Felis catus) in the Tropics of Mexico

The objective of this study was to determine the seasonal ovarian activity of domestic queens under the tropical conditions of southern Mexico (19° 30' and 21° 35' N latitude). A total of 250 reproductive tracts were evaluated, and the frequencies of queens with ovarian activity (oestrus, dioestrus or pregnant), anoestrus, pregnancies and ovulation rate by season of the year (spring, summer, autumn and winter) were calculated. Ovarian activity was observed throughout the year, but a significant reduction occurred during the winter; conversely, anoestrous cases were lower during spring and showed an increase during summer, autumn and winter. Pregnancies were most common during spring and decreased during summer, autumn and winter. Ovulation rate varied from 2.5 to 2.8 during the four seasons. Cystic endometrial hyperplasia, pyometra and ovarian follicular cysts were the most common lesions found. The results demonstrate that domestic queens are not seasonal in tropical conditions, but a clear effect of the season of the year reducing ovarian activity is present.

English

Considering the fact that in Romania, the vast majority of tomatoes harvest comes from the farmers who have relatively small areas of solariums and greenhouses, between 100 and 2000 sqm, farmers are always looking for new hybrids with the special produc- tive performance in low temperature conditions corresponding to beginning of spring, with resistance to diseases and pests. Aim of this study was to test and recommend farmers from the south of Romania's new tomatoes hybrids with outstanding performance for the culture in solar of the tomatoes in conventional system (culture on soil) with early production. In this context, it has studied 11 hybrids the Israeli provenance tomatoes. Among hybrids analyzed, the best results in relation to the tomatoes productive potential per 1m 2 were obtained for 3319 hybrid noted V8 with a production of 16.667 kg/m2 under the conditions of the early spring with a day maximum temperature of 20°C. In addition, although this hybrid germinated least (only 87% of seeds) and later towards others tested (after 11 days) had the highest early produc- tion 9.060kg/m2 at first harvest from July 1. In terms of storage conditions at 9°C, the best behavior has had the hybrid 3351 whose firmness was kept undisturbed for 2 weeks. Such meticulous tests concerning the overall development of hybrids of germination, growth, flowering and production showed the im- portance of these experiments to identify the most suitable hybrids for envisaged climatic conditions and culture. In this specific, case the hybrid 3319.

Spawning of migratory fish species between two reservoirs of the upper Uruguay River, Brazil

This study investigated the migratory fish spawning within the reservoirs of the Machadinho and Itá dams (upper Uruguay River, Brazil) and its relationship to environmental variables. Sampling was conducted in the lotic region of the river in two sites between the dams' reservoirs: Uruguay (main river) and Ligeiro (tributary). Sampling included nine consecutive reproductive periods (RP) spanning the period from 2001 to 2010 and was conducted at night on the water surface using cylindrical-conical plankton nets (0.5 mm mesh); environmental variables were also recorded. The spawning of the migratory species Salminus brasiliensis, Prochilodus lineatus, and Steindachneridion scriptum was registered: S. brasiliensis and P. lineatus spawned in the tributary river at the end of spring/beginning of summer, during flooding and during periods of high water temperature. Steindachneridion scriptum spawned in the main river at the beginning of spring. The study showed that S. brasiliensis, P. lineatus, and S. scriptum are able to spawn in small lotic river stretches within two reservoirs, but only under very specific and not common environmental conditions.