Cm In Height Research Articles

A Deployable Conical Log Spiral Antenna for Small Spacecraft: Mechanical Design and Test

We present the design and manufacturing of a deployable conical log spiral spring antenna for small spacecraft, along with a test campaign to evaluate its suitability for space applications. The conical spring was 45.7 cm in height, with base and apex diameters of 18.9 and 2.8 cm, respectively. The spring had a mass of 0.138 kg and was constructed from a carbon fiber-infused epoxy matrix with an embedded coaxial cable. We conducted dynamic and thermal mechanical analysis to determine the coefficient of thermal expansion and glass transition temperature. The initial 10 compressions of the spring shortened the structure’s overall height, but the change had a negligible effect on the antenna’s radio frequency (RF) performance. Thermal cycling between −70 °C and 80 °C did not cause any damage or deformation to the spring structure. Outgassing tests were conducted in a thermal vacuum chamber, and the total mass loss was 0.03%. We conducted vibration tests representative for a typical launch vehicle, and all natural frequencies remained stable above 250 Hz, while the antenna was stowed, satisfying launch vehicle requirements. Post-test functional checks confirmed that there was no change in antenna functionality. The environmental test results provide confidence that the antenna is suitable for spacecraft applications.

Fertiliser Placement in Relation to Root Formation for Peat Soil Mounded Oil Palm

In peat soils, leaning and toppling over of even healthy palms is a common feature. This can pose serious problems to estate operations, in addition to causing a significant decline in palm productivity and yield. To check this problem, some plantation companies in Indonesia have resorted to large scale soil mounding. In most cases, soil mounding is initiated when palms are six years old and above, having adequate trunk height and canopy clearance. Dimensions of individual soil mounds can range from 50 – 100 cm in height and 100 – 150 cm in radius. A common question often raised about soil mounded palms is where best to apply the fertiliser? Do you apply it on the mound or beyond the mound in the inter-row or inter-palm spaces? If it is to be applied on the mound, does the mound have sufficient newly developed roots to absorb the fertiliser? As maximum uptake efficiency is achieved when fertilisers are applied over the surface area that contains the highest density of feeder roots, an investigation was initiated to determine the distribution and spread of the roots of soil mounded palms. The results from the current study found that the total root biomass in the mound comprised only 20 – 22 per cent of the total root biomass found within the mound and in the soil immediately below the mound or only 5 per cent of the total root mass occurring within a radius of 3.5 m from the palm bole. The low percentage of roots inhabiting the mound indicates that the main benefit of soil mounding is unlikely to be through enhancement of new root growth (anchorage), but mainly to physically prop-up the palms. The study also concurred with earlier findings that there was a significant decline in root biomass with increasing distance from the palm bole. On average, 83 per cent of all roots were found growing within the weeded palm circles (0-2.0 m radius) and only 17 per cent outside the latter (2.0 – 3.5 m). As in previous studies, the horizontal distribution of the roots was strongly correlated with a fertility gradient especially potassium, which also declined in concentration away from the bole. The development of such a fertility gradient was attributed not to natural soil resources, but due to historical fertiliser placement practices. Based on current and previous findings, recommendations for the application of both macro and micro nutrient fertilisers for soil mounded oil palms are provided in this paper. Keywords : Fertilisers, oil palm, peat, roots, soil mounding.

Evaluating the Elastic Modulus of Geopolymer Concrete: The Impact of Fly Ash as a Cement Substitute using a No-Soaking Method for Sustainable Construction

The mechanical properties of concrete play a crucial role in determining its structural performance, particularly its modulus of elasticity, which reflects its deformation resistance under stress. This study investigates the influence of fly ash as a partial cement substitute on the elastic modulus of geopolymer concrete produced using a no-soaking method. Experimental analysis was conducted in accordance with ASTM C469-2, utilizing cylindrical specimens (15 cm in diameter and 30 cm in height) to evaluate the effects of fly ash at replacement levels of 5%, 10%, and 15%. The findings reveal that the incorporation of fly ash significantly influences the elasticity of geopolymer concrete, with measured elastic modulus values of 24.78 MPa, 23.43 MPa, and 21.46 MPa for 5%, 10%, and 15% fly ash substitution, respectively, compared to 20.60 MPa for conventional concrete. The results indicate that a 5% fly ash substitution yields the highest modulus of elasticity, suggesting an optimal balance between pozzolanic reactivity and microstructural densification. However, further increases in fly ash content exhibit a declining trend, potentially due to reduced early-age hydration contributions. This study highlights the potential of fly ash as a sustainable alternative to traditional cement, offering insights into its mechanical performance and implications for eco-friendly construction practices.

Gait spatio-temporal characteristics during obstacle crossing as predictors of fall risk in stroke patients

BackgroundSpatio-temporal parameters provide reference information for the gait variations of stroke patients during obstacle crossing. Analyzing these gait spatio-temporal characteristics of patients during obstacle crossing can assist in assessing the risk of falls. The aim of this study was to analyze the variances in gait spatio-temporal characteristics during obstacle crossing between stroke patients with and without a history of falls, to explore spatio-temporal parameters for assessing fall risk, and to construct a regression model for predicting patients’ fall risk.MethodsThirty-three patients with unilateral brain injury from stroke who were discharged from rehabilitation were included. These patients were categorized into a falls group (with a history of falls) and a non-falls group (without a history of falls) based on whether they had experienced a fall in the previous six months. A Qualisys motion capture system was used to record the marker positions when crossing an obstacle 4 cm in height with the affected leg as the leading limb, and gait spatio-temporal parameters were calculated and obtained. Univariate analysis and logistic regression models were used to compare the gait spatio-temporal parameters of the two groups.Results17 participants were categorised into the falls group and 16 into the non-falls group. The single support phase of leading limb, post-obstacle swing phase of trailing limb, obstacle-heel distance of leading limb, and obstacle-heel distance of trailing limb were significantly smaller in the fall group compared to the non-fall group (P < 0.05). The gait spatio-temporal parameter ultimately included in the fall risk prediction model was the obstacle-heel distance of leading limb (OR = 0.819, 95%CI = 0.688–0.973, P = 0.023). The overall correct classification rate from this model was 69.7%, and the area under the curve (AUC) was 0.750 (P = 0.014).ConclusionAbnormalities in gait spatio-temporal parameters during obstacle crossing in stroke patients can contribute to an increased risk of falls. The fall risk prediction model developed in this study demonstrated excellent predictive performance, indicating its potential utility in clinical settings.

Optimizing sampling across transect-based methods improves the power of agroecological monitoring data.

Transect-based monitoring has long been a valuable tool in ecosystem monitoring to measure multiple ecosystem attributes. The line-point intercept (LPI), vegetation height, and canopy gap intercept methods comprise a set of core methods, which provide indicators of ecosystem condition. However, users often struggle to design a sampling strategy that optimizes the ability to detect ecological change using transect-based methods. We assessed the sensitivity of each of these core methods to transect length, number, and sampling interval in 1-ha plots to determine: (1) minimum sampling required to describe ecosystem characteristics and detect change; and (2) optimal transect length and number to make recommendations for future analyses and monitoring efforts. We used data from 13 National Wind Erosion Research Network locations, including five LTAR sites, spanning the western United States, which included 151 plot sampling events over time across five biomes. We found that longer and increased replicates of transects were more important for reducing sampling error than increased sample intensity along fewer transects per plot. For all methods and indicators across biomes plots, three 100-m transects reduced sampling error such that indicator estimates fell within a 95% confidence interval of±5% for canopy gap intercept and LPI-total foliar cover,±5cm for height, and±2 species for LPI-species counts. For the same criteria at 80% confidence intervals, two 100-m transects are needed. Site-scale inference was strongly affected by sample design, consequently our understanding of ecological dynamics may be influenced by sampling decisions.

Randall Foils Versus Big Blades: Comparative Analysis in On-Water Sprint Rowing.

We evaluated the technical and energetical impact of using Randall foils versus simple Big blades during a maximum rowing effort in field conditions. Fourteen experienced rowers (12 male and 2 female) 26 (9) versus 25 (9)years of age, 179.8 (4.3) versus 175.0 (2.8)cm in height, and 74.2 (4.8) versus 65.5 (6.2)kg of body mass (for males and females, respectively) performed 2 maximal 500-m on-water bouts (1 each using Randall foils and simple Big blades in a randomized order). Performance and physiological variables were continuously measured along the efforts, with the latter being also recorded during the baseline and recovery periods. Rowing time was shorter using Randall foils when compared with simple Big blades (107.59 [5.53] vs 108.96 [5.44]s), while cycle rate (39.73 [2.56] vs 39.71 [2.24]cycle·min-1), peak oxygen uptake (63.47 [9.96] vs 62.68 [9.65]mL·kg-1·min-1), mean oxygen uptake (4.15 [0.77] vs 4.12 [0.78]L·min-1), respiratory frequency (62.44 [9.22] vs 62.17 [11.22] beats·min-1), peak heart rate (178 [11] vs 180 [9]beats·min-1], peak blood lactate concentration (14.26 [3.52] vs 13.76 [4.02]mmol · L-1), and rating of perceived effort (17 [1.43] vs 17 [1]) were similar in both experimental conditions. Furthermore, it was observed that the aerobic pathway represented ∼50% of the total energy spent in the 500-m sprint independently of the blades used. Data suggest that the use of Randall foils enhances rowing performance without compromising rowers' mechanical and metabolic functions.

Astragalus helanshanensis, a new plant species from the arid region of the Helan Mountains in northwestern China

Astragalus helanshanensis is a newly identified species found on the floodplain fan at the southern end of the Helanshan Mountains in northwestern China. This leguminous plant is 3–5 cm in height, with extremely short, condensed stems and subappressed hairs throughout. Leaves 2–4 cm long; rachis persistent, leaflets always 2 pairs, mostly inserted on the upper 1/3 of petiole, opposite; 1–3 flowered; flag petal tips retuse, pterygoid limb notched; keeled limb 1/2 as long as petiole; pods ovate-elliptic, 10–12 mm long, densely covered with white subappressed hairs, bipinnate. The discovery of this species enriches the known diversity of Astragalus and provides a scientific basis for the ecological protection and utilization of these plant resources in the Helan Mountains, while further advancing our understanding of the evolution and ecology relationships of the Astragalus genus.

ANALISIS INTERAKSI TANAH-GEOFOAM TERHADAP PARAMETER KUAT GESER TANAH

The ground in the Gedebage area of Bandung city consists of soft soil at a depth of approximately 30 meters. Construction on soft soil generally suffers from high settlement and low bearing capacity. To overcome the problem of soft soil, a lightweight material solution is needed that still has the necessary strength. This research uses geofoam, a synthetic material made of EPS (expanded polystyrene), as a geotechnical material. The interaction between soil and geofoam has not been widely studied, while the use of interface value software applications are always required for the geotechnical analysis process. This study aims to analyze the effect of geofoam layer on soil shear strength parameters in Gedebage area, Bandung and geofoam interaction. The soil samples used were undisturbed soil at a depth of 2.0-2.5 meters. The test conducted was the consolidated drained (CD) type direct shear test using geofoam of PT X with the type of Geofoam EPS with geofoam sample dimensions for testing 6 cm in diameter and 1 cm in height. The results showed that the Geofoam affected the shear strength parameters of the native soil. In the direct shear test of the native soil, the cohesion value (c) was found to be 0.0392 kgf/cm2 and the internal shear angle was 23.44 degree. While in the direct shear test of native soil with Geofoam, the cohesion value (c) was 0.5598 kgf/cm² and the internal shear angle was 7.02 degree. The Rinterface value of the interaction between soil and Geofoam is 0.284

An Untethered Soft Snail Robot Steers with a Single Motor.

Achieving strong adaptability and high-load capacity for small-scale soft robots remains a challenge in current robotics engineering. In this study, inspired by a snail movement, we developed a soft crawling robot capable of controllable locomotion and carrying a load of 204 g-7.7 times its own weight-using just one single motor for robot control. The robot measures 7.6 cm in length, 3 cm in width, and 2.5 cm in height, with a total weight of 26.5 g. The anisotropic friction mechanism on the robot's bottom, comprising a soft origami-based pad and asymmetrical sawtooth structure, enables its strong adhesion to stick to and simultaneously crawl (transitional adhesion) on many surfaces. This design allows the robot to move at speeds up to 3 mm/s and climb a slope of 35° inclinations, also making it suitable for various uneven terrains. Additionally, the robot has enhanced cross-environmental capabilities due to its ability to glide on the water. This research advances the development of relatively simple small-scale single-actuator robots, providing insights into their potential for flexible movement, high-load capacity, and potential swarming behavior.

Gender Differences in Joint Biomechanics During Obstacle Crossing with Different Heights.

Identifying gender-related gait changes offers valuable insights into the role of gender in motor control. It is anticipated that more difficult gait tasks (obstacle crossing) may reveal gender-specific effects on gait parameters. The present study aimed to explore the gait adaptations of male and female participants when stepping over obstacles of 0 cm, 13 cm, 19 cm, and 26 cm in height. A total of 12 male and 12 female participants were recruited. The Vicon motion capture system and AMTI force plates were utilized to obtain the gait parameters. Moreover, spatiotemporal parameters were investigated. Two-way repeated ANOVA (gender × obstacle height) and three-way repeated ANOVA (gender × obstacle height × leg) were performed to compare gait parameters, respectively. Correlations between maximum joint angle and obstacle height were also evaluated. Significant interactions were observed for leading leg swing time, maximum hip extension angle, maximum knee flexion angle, and maximum ankle plantarflexion angle (gender × obstacle height). There were some differences in gait parameters between males and females in the unobstructed gait, and these changes became more evident as obstacle height increased. This study also identified significant differences in gait parameters between leading and trailing legs when stepping over the obstacle.

First Report of Botryosphaeria dothidea Causing Canker of Calocedrus decurrens in Tennessee.

Incense cedar (Calocedrus decurrens) is a conifer native to the western United States, valued for its low maintenance and aesthetic appeal in ornamental landscapes. In May 2024, field and container grown incense cedar exhibited canker and dieback in a USDA research plot at the Nursery Research Center, McMinnville, TN (Fig. 1a). Disease incidence was 60% of a total 100 plants. For isolation of the causal agent, small pieces (∼0.3 mm2) of the branch and stem cankers were excised, surface sterilized with 1% sodium hypochlorite for 1 minute, followed by 70% ethanol for 30 seconds, and washed twice with sterile water. The pieces were placed on potato dextrose agar (PDA) and incubated at 25°C under 12-hour light/dark conditions. Colonies initially appeared white, and after four to six days, they gradually turned dark gray with dense aerial mycelia (Fig. 1b). Conidia produced within pycnidia after 3 weeks were hyaline, fusiform, and aseptate, with dimensions of 21.1 to 25.8 μm (avg. 24.35 ± 1.049 μm) in length and 5.7 to 8.2 μm (avg. 6.1 ± 0.687 μm) in width (n = 50) (Fig. 1c). Pathogen identity was confirmed by extracting total genomic DNA using the DNeasy PowerLyzer Microbial Kit from 7-day-old pure cultures (isolates FBG7412 and FBG7413). The primer pairs ITS1/ITS4 (White et al. 1990), T1F/Bt2b (Glass and Donaldson 1995; O'Donnell and Cigelnik 1997), and EF1-728F/EF2 (Carbone and Kohn 1999) were used to amplify the ribosomal internal transcribed spacer (ITS), and nuclear beta-tubulin (TUB) and translation elongation factors 1-α (EF1-α) genetic markers, respectively. The sequences of the two isolates (FBG7412 and FBG7413) were deposited in GenBank with accession numbers PQ482605 and PQ482606 (ITS); PQ493369 and PQ493370 (TUB); and PQ493366 and PQ493367 (EF1-α), respectively. GenBank BLAST search of sequences using the core nt database showed 100% identity (100% coverage) of ITS, TUB, and EF1-α sequences to Botryosphaeria dothidea isolates IS2116-1 (OR958722), MEND-F-0379 (OQ994765), and IRNBS19 (MN633962), respectively. Phylogenetic analysis of concatenated ITS, TUB, and EF1-α sequences confirmed the pathogen as B. dothidea (Fig. 2). Two same two fungal isolates FBG7412 and FBG7413 were used to inoculate incense cedar cuttings grown in 3.8L pots with each plant measuring 12-15 cm in height. The inoculum was prepared by growing each isolate on PDA for one week at 25°C. For inoculation, a thin slice of bark (4 mm²) was removed from the stem of each cutting, and a 4-mm-diameter plug colonized by the fungal isolate was placed on the wound which was then covered with Parafilm. Negative controls were mock inoculated with sterile PDA plugs. There were five replications for each isolate and control. The study was conducted in a greenhouse maintained at 23-25°C and 70% relative humidity, with a 16-hour photoperiod. Six weeks post-inoculation, the branches inoculated with B. dothidea exhibited browning and dieback while the controls remained green and healthy (Fig. 1d-f). A dark, necrotic lesion that extended up and down from the inoculation point gradually spread to kill the main stem. Fungal isolate (FBG7703) with the same morphology and DNA sequences as FBG7412 and FBG7413 were recovered from the symptomatic stems of the inoculated plants. Control plants remained symptomless, and B. dothidea was not isolated from them. B. dothidea was previously isolated from incense cedar in California (Ma and Michailides 2002). To our knowledge, this is the first report of B. dothidea causing canker disease in incense cedar in Tennessee. Accurately identifying this pathogen as the causal agent is important for developing effective and timely management strategies.

WOODY SPECIES CULTIVATED FOR ORNAMENTAL PURPOSES WITH INVASIVITY CAPACITIES IN OLTENIA, ROMANIA

Changes in climatic conditions influence the expansion on ever larger surfaces as well as the exacerbated development of populations of invasive species introduced in southern Romania initially for ornamental purposes. In the last decades, an increasing number of species that were cultivated for different purposes but also that accidentally entered Oltenia became successful invaders in different habitats. Many factors may contribute to the increased invasiveness of these species, including seed production, germination, and their relatively high growth rate. The impact of invasive species on native vegetation in a region can have different intensities, but they can increase with the accentuation of the drought and the aridification of the lands in the south of Oltenia, this may lead to the loss or irreversible degradation of habitats or species populations. In recent years in Oltenia, especially in the southern part, in the large hydrographic basins of the Danube, Jiu and Olt, the number of invasive species has increased considerably, their ability to spread and invasiveness being very high. Some of these species exert a high degree of aggression on wet, practical and forest habitats, influencing the structure and functionality of edifying phytocoenoses. Among the invasive species introduced for ornamental purposes in Oltenia, particularly important populations have developed: Acer negundo, Rhus typhina, Amorpha fruticosa, Ailanthus altissima, Eleagnus angustifolia, Fraxinus pensylvanica, F. americana, Parthenocissus inserta, P. quinquefolia, Robinia hispida. It should be noted that in recent years the species Albizia julibrissin was introduced for ornamental purposes in Romania, but also in Oltenia. This species is cultivated excessively, in gardens, green spaces, private yards and especially in the open spaces in front of private yards in most locations in Oltenia. Following the studies carried out regarding the invasive potential of this species, we can mention the fact that this species has a very high spreading power, quickly conquering new territories, each individual produces a very large number of seeds that have a very high germination power, is a species extremely resistant to drought, to various anthropogenic factors, including atmospheric pollution, to harmful mechanical factors, very high temperatures of over 400 during the summers in the south Oltenia, growing on the sides of roads, alleys, on several types of soil, including sandy. Around each individual, but also at distances between 2-80 m from it, vigorous saplings were identified, with increased vitality and accelerated growth, being able to reach up to 30-40 cm in height in one year of vegetation. Thus, we can specify that this species can be considered a new invasive species for Romania.

Discharge Coefficient of a Compound Weir with a Triangular underneath Gate for Different Geometric and Hydraulic Conditions

It is common practice in the field of irrigation systems to use composite hydraulic structures, which are constituted of two distinct parts. The initial component, represented by two rectangles, is responsible for the overflow regime, while the subsequent component, represented by a triangular gate, is responsible for the underflow regime. In order to measure, direct, and control the flow, both components are required. The present study investigates the flow through a combined two-rectangle weir with a below-triangular gate across the channel, which serves as a control structure. The weir's upper rectangle has a constant width, designated as b1 and measuring 20 cm, while the lower rectangle has a variable width, designated as b2 and comprising the values of 8 cm, 10 cm, and 12 cm. The depth of the lower rectangle, z, is also a variable with values of 6 cm, 9 cm, and 11 cm. The dimensions of the triangular gate are 15 cm in height and 0, 60, 90, or 120 degrees in vertex angle. The aforementioned dimensions were employed interchangeably as geometric conditions and the disparate water heads h2 as hydraulic conditions. Additionally, the compound weir devoid of a gate (θ = 0) was used for varying water heads. The results demonstrated that the dimensions of the weir and gate had an impact on the discharge that went through the two rectangular weirs and gates. In terms of discharge capacity, the combined structure was observed to be more effective than a classic weir, with the ability to convey a discharge that was two to ten times greater. An empirical formula was developed to predict the discharge coefficient, Cd, for the combined structure, based on the given geometric and hydraulic conditions. It should be noted that the results and analysis of this study were limited to the tested dataset.

Biomass production and silage quality of ensiled BRS Capiaçu elephant grass at different regrowth ages and residue heights

The aim of this study was to determine the optimal combination of regrowth age and residue height of BRS Capiaçu elephant grass that yields the best balance between the dry mass production (DMP) of the harvested forage and silage quality. Four regrowth ages (75, 90, 105, and 120 days) and two residue heights (10 and 50 cm) were evaluated. The experimental design used a randomized complete block design with a 4 × 2 factorial scheme and 3 replicates. The regrowth age led to a linear increase in DMP. As regrowth age advanced, there were linear increases in the dry matter (DM) concentration, cell wall constituents, and fraction C (acid detergent insoluble nitrogen) of crude protein and reductions in the in vitro digestibility of DM and neutral detergent fiber (IVNDFD) in both the plant and its silage. Lower pH values were observed in silage made from plants harvested at 10 cm. No significant effects of the studied factors were found on the concentrations of organic acids in the silage, except for propionic acid. Management using a 105-day regrowth period and a 10-cm residue height resulted in a better balance between the dry mass production, fermentative profile and nutritional value of silage.

An ivory statuette depicting the god Thanatos discovered near Tomis (Moesia Inferior)

In recent years, real estate developments in Constanța prompted a series of preventive archaeological investigations, leading to the discovery of rich archaeological material. These finds include a bone statuette found in the Palazu Mare district of Constanța. In this context, the nucleus of habitation, previously inferred from various archaeological finds from the Roman period, has been identified. Numerous surveys and preventive archaeological investigations have allowed for a clearer delimitation of the archaeological site of Palazu Mare. Regarding chronology, the settlement (possibly a vicus) can be dated from the 2nd–3rd centuries to the early decades of the 4th century AD. The statuette in question was carved out of ivory, measuring 6 cm in height and 1.7 cm in width. It was made as a representation of the god Thanatos, the personification of the Angel of Death in Greek and Roman mythology. Unfortunately, the statuette is incomplete; the left hand and parts of the legs are missing, along with the wings originally located on its back. The closest analogy for our representation comes from Northern France, where a small bronze statue was discovered in a villa rustica in Salouël, a commune located on the outskirts of Amiens. Due to the uncertainty surrounding the function of the object to which the statue pertains, we classify it as instrumentum domesticum, a category that includes a variety of objects that were part of everyday Roman life. The discoveries made here are considered quite rare due to the material of the statuette, and the context in which it was found. Based on previous observations, it can be said that Thanatos is typically a characteristic of funerary art and is therefore rarely found in domestic contexts. Ivory statues are particularly uncommon in the Dobrudja region of Moesia Inferior.

Combined Effects of Nitrogen Deposition and Climate on Root-to-Shoot Ratios and Root Morphology in Temperate Tree Regeneration

Nitrogen (N) availability is known to interact with the drought tolerance in plants, but its effects on the morphological acclimation of forest trees to low precipitation have rarely been investigated. Based on a Germany-wide field-study design covering different combinations of climatic conditions and atmospheric N deposition, we harvested young trees up to 70 cm in height of Fagus sylvatica, Quercus petraea, Pseudotsuga menziesii, and Abies alba. We tested the hypothesis that high N deposition decreases the root/shoot ratio, alters fine root morphology (for example, by reducing specific root length of absorptive roots) and reduces mycorrhizal colonization rate, which are factors that would reduce the capacity for water uptake under drought. European beech showed reduced root/shoot ratios at high N deposition and reduced specific root length and mycorrhizal colonization of absorptive roots at sites with both high N deposition and low precipitation. These observations were consistent with the optimal portioning theory, as less investment in belowground biomass was required to meet the N demand at high N deposition. Sessile oak showed no effect of N deposition or mean annual precipitation on the parameters studied, indicating that the gradients studied were not large enough to cause changes. Douglas-fir and silver fir expanded their root systems with increasing N deposition, with higher specific root length in Douglas-fir and a trend towards higher root tip abundance in silver fir. Thus, in contrast to European beech, we found no indication that the tree's ability to cope with drought was reduced by high N deposition in sessile oak, Douglas-fir, and silver fir. The combined negative effect of drought and high N deposition on the root system in European beech as Central Europe’s most dominant tree species in the natural vegetation emphasizes the need for curtailing N emissions, especially from agriculture.

Identification of the Morphology of Tamarix spp in the Mexicali Valley, Baja California, Mexico

Objective: The predominant species of Tamarix spp in the Mexicali Valley is unknown, and due to the scarce information available, this study aims to expand the knowledge of the morphology of Tamarix spp in the Mexicali Valley, Baja California, Mexico. Design/methodology/approach: For this research, five branches with inflorescences and roots of Tamarix spp trees were collected from four selected locations in the Mexicali Valley. The collection was carried out during the flowering season from March to August, considering branches between 2.50 and 3.50 cm in height. The morphological descriptions were based on fresh plants using an Olympia optical microscope. Results: After the morphological analysis was carried out at the different sampling sites, the predominant salt cedar genotype found in the Mexicali Valley corresponded to Tamarix chinensis. In addition, it was found high electrical conductivity measured in the upper soil layer (20 cm depth) was found to be caused by the excretion of salts through the glands of the leaves of this species. Consequently, salt cedar species can inhibit other vegetation types, although it can benefit honey bee production. Findings/conclusions: Tamarix chinensis was the predominant salt cedar species throughout the sampling sites under the conditions of this study.The high electrical conductivity measured in the upper soil layer (20 cm depth) shows that salt cedar species can inhibit the growth of other vegetation types, although it can be beneficial for honey bee production.

Postemergence giant ragweed management as affected by soil and cover crop management, soybean planting time, and preemergence herbicide application

Abstract Early soybean planting and cover crop adoption in the US Midwest prompt investigation into the impact of these practices on weed community dynamics and best management practices. While previous research has explored different aspects of giant ragweed control, the specific integration among soil management practices, including cover crop adoption, soybean planting timing, and herbicide use, has not been thoroughly investigated. This study assessed soil management, soybean planting time, and PRE herbicide application on giant ragweed control and soybean yield in Wisconsin and Nebraska in 2022 and 2023. The study included a factorial arrangement of four soil management treatments [conventional tillage, no-till, and fall-planted cereal rye early terminated and terminated at planting (planting green)]; two soybean planting times; and two PRE herbicide treatments (PRE and no PRE). Postemergence (POST) herbicides were applied when ∼50% of giant ragweed plants within each treatment reached ∼10 cm in height. In Nebraska, cereal rye and tillage treatments without a PRE had at least 67% lower giant ragweed density than no-till at POST. In no-till, densities were at least 60% lower with PRE compared to no PRE. In Wisconsin, cereal rye did not reduce giant ragweed density at POST compared to no-till, likely due to relatively low biomass accumulation. In contrast, delayed soybean planting reduced giant ragweed density for most treatments but lowered soybean yield in no-till and planting green treatments. The PRE herbicides had either no or positive effects on reducing giant ragweed density and increasing soybean yield. Overall, this study suggests that soil management and soybean planting timing are crucial for effective giant ragweed management in Wisconsin, where biotypes with a long emergence window during the spring and summer are present, while in Nebraska, soil management and soybean planting timing are less critical due to giant ragweed biotypes with an early and short emergence window in the spring.

Weather and glufosinate efficacy; a retrospective analysis looking forward to the changing climate

Abstract Foliar-applied postemergence applications of glufosinate are often applied to glufosinate-resistant crops to provide nonselective weed control without significant crop injury. Rainfall, air temperature, solar radiation, and relative humidity near the time of application have been reported to affect glufosinate efficacy. However, previous research may have not captured the full range of weather variability to which glufosinate may be exposed to prior to or following application. Additionally, climate models suggest more extreme weather will become the norm, further expanding this weather range glufosinate can be exposed to. The objective of this research was to quantify the probability of successful weed control (efficacy ≥85%) with glufosinate applied to some key weed species across a broad range of weather conditions. A database of &gt;10,000 North American herbicide evaluation trials was used in this study. The database was filtered to include treatments with a single POST application of glufosinate applied to waterhemp (Amaranthus tuburculatus (Moq.) J. D. Sauer), morningglory species (Ipomoea spp.), and/or giant foxtail (Setaria faberi Herm.) &lt;15cm in height. These species were chosen because they are well represented in the database and listed as common and troublesome weed species in both corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] (Van Wychen 2020, 2022). Individual random forest models were created. Low rainfall (≤20 mm) over the five days prior to glufosinate application was detrimental to the probability of successful control of A. tuburculatus and S. faberi. Lower relative humidity (≤70%) and solar radiation (≤23 MJ m-1 day-1) the day of application reduced the probability of successful weed control in most cases. Additionally, the probability of successful control decreased for all species when average air temperature over the first five days after application was ≤25C. As climate continues to change and become more variable, the risk of unacceptable control of several common species with glufosinate is likely to increase.

Efeito da adição de Megathyrsus maximus em ração total mista sobre desempenho, metabolismo e qualidade de carcaças de cordeiros

ABSTRACT: This study assessed the impact of total mixed ration silage of Megathyrsus maximus harvested with 70 cm composed of Megathyrsus maximus harvested at 70 cm in height and concentrate at the time of silage or total mixed ration of grass cut at 70 cm composed of Megathyrsus maximus harvested with 70 cm in height (in Exp. I and III) and total mixed ration silage cut at 130 cm composed of Megathyrsus maximus harvested 130 cm height and concentrate at the time of silage or total mixed ration of Megathyrsus maximus harvested with 130 cm composed of Megathyrsus maximus harvested at 130 cm height (in Exp. II and IV), on rumen metabolism, nutrient digestibility, and the performance and carcass characteristics of feedlot lambs. The results showed that TMRS70 increased ruminal pH in Exp. I and TMRS130 exhibited higher ether extract digestibility, propionic concentration, and lower acetic to propionic ratio and ruminal pH compared to TMR130 in Exp. II. In Exp. III and IV, there was no significant effect on the performance and quality of the carcass. However, in Exp. IV, TMRS130 led to decreased dry matter intake and average daily gain, while lambs fed with TMR130 showed a higher rib-eye area. Total ration ensilage could be used as a conservation method for young grasses (70 cm) without impairing performance, metabolism, carcasses, and meat quality. However, further research is recommended to evaluate the economic analysis of feeding total ration ensilage (70 cm) instead of total mixed ration as a forage conservation method.