Variability in spawning frequency and reproductive development of the narrow-barred Spanish mackerel (Scomberomorus commerson) along the west coast of Australia

The narrow-barred Spanish mackerel (Scomberomorus commerson) is widespread throughout the Indo-West Pacific region. This study describes the reproductive biology of S. commerson along the west coast of Australia, where it is targeted for food consumption and sports fishing. Development of testes occurred at a smaller body size than for ovaries, and more than 90% of males were sexually mature by the minimum legal length of 900 mm TL compared to 50% of females. Females dominated overall catches although sex ratios within daily catches vary considerably and females were rarely caught when spaw n ing. Scomberomorus commerson are seasonally abundant in coastal waters and most of the commercial catch is taken prior to the reproductive season. Spawning occurs between about August and November in the Kimberley region and between October and January in the Pilbara region. No spawning activity was recorded in the more southerly West Coast region, and only in the north Kimberley region were large numbers of fish with spawning gonads collected. Catches dropped to a minimum when spawning began in the Pilbara region, when fish became less abundant in inshore waters and inclement weather conditions limited fishing on still productive offshore reefs. Final maturation and ovulation of oocytes took place within a 24-hour period, and females spawned in the afternoon-evening every three days. A third of these spawning females released batches of eggs on consecutive days. Relationships between length, weight, and batch fecundity are presented

Term limits boost turnout in state legislative elections

In recent years, some commentators have proposed introducing Congressional term limits as a way of decreasing gridlock in the US House and to increase the public's trust for politicians. But would such limits actually be effective in re-energizing the democratic process? Daniel C. Lewis and Robynn Kuhlmann examine the effects of term limits in the 15 US states that have introduced them since the 1990s. They find that term limits can significantly increase voter turnout as well as encouraging people to vote in down-ballot races

Do stiffness and asymmetries predict change of direction performance?

Change of direction speed (CODS) underpins performance in a wide range of sports but little is known about how stiffness and asymmetries affect CODS. Eighteen healthy males performed unilateral drop jumps to determine vertical, ankle, knee and hip stiffness, and a CODS test to evaluate left and right leg cutting performance during which ground reaction force data were sampled. A step-wise regression analysis was performed to ascertain the determinants of CODS time. A two-variable regression model explained 63% (R-2 = 0.63; P = 0.001) of CODS performance. The model included the mean vertical stiffness and jump height asymmetry determined during the drop jump. Faster athletes (n = 9) exhibited greater vertical stiffness (F = 12.40; P = 0.001) and less asymmetry in drop jump height (F = 6.02; P = 0.026) than slower athletes (n = 9); effect sizes were both "large" in magnitude. Results suggest that overall vertical stiffness and drop jump height asymmetry are the strongest predictors of CODS in a healthy, non-athletic population

The mitochondrial Na+/Ca2+ exchanger upregulates glucose dependent Ca2+ signalling linked to insulin secretion.

Mitochondria mediate dual metabolic and Ca(2+) shuttling activities. While the former is required for Ca(2+) signalling linked to insulin secretion, the role of the latter in β cell function has not been well understood, primarily because the molecular identity of the mitochondrial Ca(2+) transporters were elusive and the selectivity of their inhibitors was questionable. This study focuses on NCLX, the recently discovered mitochondrial Na(+)/Ca(2+) exchanger that is linked to Ca(2+) signalling in MIN6 and primary β cells. Suppression either of NCLX expression, using a siRNA construct (siNCLX) or of its activity, by a dominant negative construct (dnNCLX), enhanced mitochondrial Ca(2+) influx and blocked efflux induced by glucose or by cell depolarization. In addition, NCLX regulated basal, but not glucose-dependent changes, in metabolic rate, mitochondrial membrane potential and mitochondrial resting Ca(2+). Importantly, NCLX controlled the rate and amplitude of cytosolic Ca(2+) changes induced by depolarization or high glucose, indicating that NCLX is a critical and rate limiting component in the cross talk between mitochondrial and plasma membrane Ca(2+) signalling. Finally, knockdown of NCLX expression was followed by a delay in glucose-dependent insulin secretion. These findings suggest that the mitochondrial Na(+)/Ca(2+) exchanger, NCLX, shapes glucose-dependent mitochondrial and cytosolic Ca(2+) signals thereby regulating the temporal pattern of insulin secretion in β cells

10 µm minority-carrier diffusion lengths in Si wires synthesized by Cu-catalyzed vapor-liquid-solid growth

The effective electron minority-carrier diffusion length, L_(n,eff), for 2.0 µm diameter Si wires that were synthesized by Cu-catalyzed vapor-liquid-solid growth was measured by scanning photocurrent microscopy. In dark, ambient conditions, L_(n,eff) was limited by surface recombination to a value of ≤ 0.7 µm. However, a value of L_(n,eff) = 10.5±1 µm was measured under broad-area illumination in low-level injection. The relatively long minority-carrier diffusion length observed under illumination is consistent with an increased surface passivation resulting from filling of the surface states of the Si wires by photogenerated carriers. These relatively large L_(n,eff) values have important implications for the design of high-efficiency, radial-junction photovoltaic cells from arrays of Si wires synthesized by metal-catalyzed growth processes

Water Quality of the North End of Seneca Lake: 1991-2006

The Seneca County Soil and Water Conservation District (SCSWCD) has collected limnological data on the waters of the northern end of Seneca Lake since 1991. This report updates the 1999 report (Makarewicz et al. 1999) with data taken by the SCSWCD from 1999 to 2006. The purpose of monitoring the northern portion of Seneca Lake was to determine the health of the Seneca Lake ecosystem and to determine if any temporal trends existed in Seneca Lake water quality. The water quality of Seneca Lake has been studied since the early 1900s when secchi disk readings were first taken. At that time, the trophic state of Seneca Lake was classified as oligotrophic; that is, nutrient concentrations and primary production were low and transparency high. Water clarity remained approximately the same up through the early 1930s. By the late 1970s, water clarity generally decreased, indicating that the lake’s trophic status was mesotrophic. Total phosphorus concentrations from the 1970s were into the mesotrophic range. Chlorophyll-a concentration also illustrated the trend toward more productive waters in Seneca Lake in the early to mid 1970s. Similarly, in the early 1970s, the transparency of Seneca Lake had decreased to within the eutrophic range. These low transparency values were observed into the early 1990s. Based on the sampling done by the Seneca County Soil and Water Conservation District from 1991 through 2006, an improvement in water quality of Seneca Lake is suggested – at least at the north end where the samples were taken. The trophic status of Seneca Lake is currently best described as oligotrophic. In conclusion, water quality of Seneca Lake appears to have improved since the early 1970s. However, the increase in total phosphorus levels from 2003 to 2005 represents an increase of some concern as they represent the highest values in the last 14 years

Water Quality Monitoring on Cratsley Gully and Honeoye Inlet, Part of the Honeoye Lake Watershed

The presence of soluble, sedimentary rocks in the watershed of the Finger Lakes determines the chemical regimes comprising the lakes (Schaffner and Oglesby 1978). As the rest of the Finger Lakes, Honeoye Lake has an abundance of calcium and bicarbonate ions (Schaffner and Oglesby 1978). Nitrate + nitrite values for Honeoye Lake in 1993 (mean = 0.02 mg/L) were significantly lower (P\u3c0.02) than levels from 1973 (mean = 0.07 mg/L) (Crego 1994). In 1973, Honeoye Lake had the highest total phosphorus (TP) concentration of the eight Finger Lakes examined (21.7 μg/L, August) (Schaffner and Oglesby 1978). However, there were no significant differences in total phosphorus and soluble reactive phosphorus (SRP) concentrations from 1973 to 1993 (Crego 1984). During the summer, Honeoye Lake’s deepest waters are not completely oxygenated and 5 experience algal blooms that impair water quality (NYSDEC Region 8). Eelgrass, pondweed, Eurasian milfoil, and water stargrass are the predominant rooted aquatic plant species that are found in near shore areas out to a depth of approximately 15 feet (~5m) (NYSDEC Region 8). The large macrophyte community (weeds) and the reoccurring blooms of algae on the lake are in part the driving force of this study. Excess nutrients, especially phosphorus, can be a major cause of an over abundance of macrophytes and algae. One source of nutrients to a lake is losses from watershed. The goal of this study was to document the level of nutrient and soil loss from the watershed into Honeoye Lake

Loss of Nutrients and Soil from Sandy Pond Tributaries, Oswego County, N.Y.

North and South Sandy Ponds comprise one of the largest coastal bay ecosystems on Lake Ontario. Unlike South Sandy Pond, North Sandy Pond supports intensive recreational activities and intensive shorefront residential development including a commercial campground and several marinas. Both ponds have an over abundance of nutrients and are the likely cause of the over abundance of aquatic weeds in the water. The limnological literature is quite clear on the causes of this unwanted overabundance of aquatic weeds and microscopic plants – an excess amount of nutrients or fertilizers are entering the water. A short list of possible sources of nutrients and soil include point and non-point sources in the watershed of Sandy Pond, septic system losses in direct drainage areas adjacent to the Pond (e.g., from cottages and boats), and resuspension of nutrients from sediments in the Pond itself. The purpose of this study was to determine the relative importance of losses of soil and nutrients from the five major tributaries draining sub-watersheds of North Sandy Pond hereafter referred to as Sandy Pond. Stream discharge and concentration of nitrate, total phosphorus, sodium, total suspended solids, and total Kjeldahl nitrogen were measured and converted into the amount of material lost from the watershed or loading into Sandy Pond during events and non-events