Black Silver Research Articles

Study on the Swimming Behavior of Black Carp (Mylopharyngodon piceus) and Silver Carp (Hypophthalmichthys molitrix) in Early Developmental Stage.

Fish need to make different responses to different water flow conditions, as a variety of fish utilize or overcome the water flow while fish are in the water. This study aims to analyze the response of two types of carp (black carp and silver carp) to water flow in different body lengths (2.0-10.0 cm) in early developmental stages in an open channel. By analyzing the water velocity and fish swimming behavior, swimming against the water flow was the most frequent swimming behavior, and the frequencies of this behavior increased with the increased body length of fish. The results demonstrated that the detectable water velocity of two carp species of different body lengths remained in a certain range (0.020-0.060 m/s). Black carp and silver carp can swim against the water flow of 0.295-0.790 m/s and 0.245-0.825 m/s, respectively. The results of this study can provide invaluable data for engineers and biologists to protect fish in the early developmental stage and restore the ecological habitats in the regulated river systems.

Elucidating the impact of environmental factors on the growth of Colletotrichum coccodes strains isolated from potato tubers in Great Britain

Black dot and silver scurf caused by Colletotrichum coccodes and Helminthosporium solani, respectively, are tuber blemish diseases affecting quality in the fresh and pre-pack potato industry. In the last 20 years, the importance of high-quality tuber appearance has increased considerably due to the growing demand for washed and pre-packed potatoes in the UK. Changing climate characterised by rising temperatures and wetter summers is a threat as this will favour the development of pathogens such as C. coccodes in the soil increasing the risk of food spoilage. Moreover, both diseases can develop not only in the field but also after harvest, with postharvest storage temperatures being a crucial factor in controlling fungal growth. Furthermore, anecdotal evidence showed differences on the aggressiveness of black dot depending on its origin (i.e. England and Scotland) on potato tubers. Silver scurf and black dot are difficult to differentiate as they present similar phenotypes characterised by silvery lesions making it challenging for managers to take the necessary corrective action during storage. Hence, the aim of this study was to give a general insight into the ecological conditions affecting the establishment of the causal agent of potato black dot in the field, and black dot and silver scurf during the supply chain. Therefore, invitro experiments were designed to study the growth rate and lag times simulating both scenarios respectively: on soil extract agar (SEA) media at different temperatures (4, 11, 15 °C) and matric potentials (control [unmodified] and − 1.4 MPa [modified]); and on natural potato dextrose agar (NPDA) for different temperatures (4, 11, 15 and 20 °C) at 99 % relative humidity (RH) for 25 days. When simulating the field environment, drier conditions (matric potential = −1.4 MPa) reduced fungal growth for both isolates by 0.1 cm day−1 at the temperature of 15 °C, suggesting temperature as the main limiting factor for the growth of C. coccodes in the soil. The causal agent of black dot exhibited a faster growth rate under retailer-like conditions (i.e., 15 °C) compared to H. solani. Understanding the environmental influence on both the pathogen and the crop is vital for proper disease management to help reduce food loss and waste.

Effects of Mulching Materials on Growth and Yield of Brinjal

Brinjal; a valuable vegetable, is susceptible to weeds and moisture stress that can hinder growth and yield. Mulching might be a good option to control weeds and moisture to enhance growth and yield. So, an experiment was conducted with five treatments viz. black silver coated mulch (BSCM; 100 gauge), black polythene mulch (BPM; 300 gauge), straw mulch (8 t ha-1), corrugated fiber box mulch (CFBM), and an unmulch group replicated for four times in randomized complete block design at Horticulture Research Station, Pokhara in 2022. Results revealed that BSCM showed the highest marketable yield (23.78 t ha-1) which was statistically similar to straw mulch (20.44 t ha-1) and BPM (19.64 t ha-1) and the lowest (12.1 t ha-1) was observed in the unmulch (12.1 t ha-1). Plant height (134.1 cm), primary root length (40.95 cm), and secondary root numbers (23.25) were observed significantly higher in BPM which was statistically similar (p>0.05) with BSCM and straw mulch. The number of branches (7.325), the fruit length (23.2 cm), and fruit diameter (2.5 cm) were found higher in BSCM. Findings suggested that applying different types of mulching materials can effectively enhance the growth and yield of brinjal.

Why Did Cyprian Norwid Wear the konfederatka?: The Crime of Wearing a Black Dress

After the partitions of Poland between Russia, Prussia and Austria, Poland disappeared from the maps of Europe. The failure of the November Uprising of 1830 against the Russian occupiers led to harsh repressions imposed by the tzarist rule on the Polish people. Many insurgents were imprisoned, or sentenced to death, or forcibly deported to Siberia, their manors and estates were confiscated, and family members were persecuted. As a result, the revival of patriotic attitudes among the subsequent generation in the Kingdom of Poland led to outburst of opposition to the imposed Russian authorities. On the 30th anniversary of the Battle of Grochów, the citizens of Warsaw organized a demonstration in the Castle Square. The Russian soldiers attacked the protesters and killed five. Around that time, a national mourning was secretly announced, and women decided to wear black dresses and silver or bone jewellery in the form of a cross or a crown of thorns, thus sending a hidden message to compatriots and to the Russians. As a result, the decree was issued against the black garments, stating that only personal mourning was allowed based on an official certificate of a family member’s death, otherwise the mourners could be imprisoned. Therefore, other colours, white and violet were introduced as a sign of resistance as well. Black dresses and the konfederatka caps meant not just fashion during the years of the January Uprising; they gained recognition as a hidden patriotic code among Poles living both in the occupied country and in emigration. Poet-emigrant Cyprian Norwid explained the importance of wearing the special type of men’s headgear, referring to the great history of his enslaved country and arguing that symbols and power of thought are powerful weapons in the modern world.

Effect of Silver Black Plastic Mulch and Organic Fertilizer Dosage on Plant Chlorophyll Growth and Content Cayenne Pepper (Capsicum annum L.)

Cayenne pepper is one of the leading horticultural products in the agricultural sector in Indonesia. In order for plants to grow optimally and produce well, it is necessary to apply silver black plastic mulch and a dose of organic fertilizer. This study aims to determine the growth and chlorophyll content of cayenne pepper plants using black silver plastic mulch and doses of organic fertilizer. The study used a randomized block design with 8 treatment combinations and 3 repetitions. The arrangement of treatments was as follows: M0P0: without mulch + 0 kg/m2, M0P1: without mulch+ 1 kg/m2, M0P2: without mulch+ 1.5 kg/m2, M0P3: without mulch+ 2 kg/m2, M1P0: MPHP + 0 kg /m2, M1P1: MPHP + 1 kg/m2, M1P2: MPHP + 1.5 kg/m2, M1P3: MPHP + 2 kg/m2. The results on plant height and leaf number observations on days 28 and 40 showed that the silver black plastic mulch factor make a real impact. Organic fertilizer significantly affected leaf length on day 40, while the interaction of silver black plastic mulch and dose of organic fertilizer affected leaf length and leaf area on day 40. The best combination in this study was black silver plastic mulch and a dose of 1.5 kg organic fertilizer/m2.

Characterization of chemical reactions of silver diammine fluoride and hydroxyapatite under remineralization conditions.

Silver Diammine Fluoride (SDF) is a clinically used topical agent to arrest dental caries. However, the kinetics of its chemical interactions with hydroxyapatite (HA), the principal inorganic component of dental enamel, are not known. The aim was to characterize the step-wise chemical interactions between SDF and HA powder during the clinically important process of remineralization. Two grams of HA powder were immersed in 10 ml acetic acid pH = 4.0 for 2 h to mimic carious demineralization. The powder was then washed and dried for 24 h and mixed with 1.5 ml SDF (Riva Star) for 1 min. The treated powder was then air-dried for 3 min, and 0.2 g was removed and stored in individual tubes each containing 10 ml remineralizing solution. Powder was taken from each tube at various times of exposure to remineralization solution (0 min, 10 min, 2 h, 4 h, 8 h, 24 h, and 10 days), and characterized using Magic Angle Spinning-Nuclear Magnetic Resonance (MAS-NMR) spectroscopy. 19F MAS-NMR spectra showed that calcium fluoride (CaF2) started to form almost immediately after HA was in contact with SDF. After 24 h, the peak shifted to -104.5 ppm suggesting that fluoride substituted hydroxyapatite (FSHA) was formed with time at the expense of CaF2. The 31P MAS-NMR spectra showed a single peak at 2.7 ppm at all time points showing that the only phosphate species present was crystalline apatite. The 35Cl MAS-NMR spectra showed formation of silver chloride (AgCl) at 24 h. It was observed that after the scan, the whitish HA powder changed to black color. In conclusion, this time sequence study showed that under remineralization conditions, SDF initially reacted with HA to form CaF2 which is then transformed to FSHA over time. In the presence of chloride, AgCl is formed which is subsequently photo-reduced to black metallic silver.

The Influence of Reflective Screen Color and Surface Film Treatment for Single-Sided Holographic Projection on Imaging Quality

This study explored the effects of reflective screen material color and film treatment in holographic projection on image quality. Employing an experimental approach, algorithmic analysis of images captured after projection was conducted to examine image quality. Image analysis was performed using OpenCV software, focusing on quantifying values of average color (RGB), contrast, sharpness, and saturation. The results revealed that changes in the reflective screen material color led to a decrease in average RGB values, by approximately 50%, compared with the transparent colorless screen. A light brown colored material demonstrated more satisfactory sharpness performance compared with the transparent colorless and black color screens. However, differences in contrast and saturation among different colored screens were not particularly noticeable. Regarding film treatment, a decrease in average RGB values for black and dark silver surface films was observed. However, light black and dark silver surface films showed a significant improvement in sharpness. Differences in contrast were not pronounced, and saturation slightly increased after film treatment. The experimental findings further showed that as the thickness of the reflective screen increased, ghosting and blurring became more noticeable at image edges. Nevertheless, tinted materials and film treatment reduced ghosting and blurring. Film treatment with low light transmittance increased surface reflectivity, which resulted in a glare effect around the images on the reflective screen, affecting the viewing experience. The results of this research may be helpful for understanding image qualities and the setting up of holographic projection reflective screens.

Effects of Mulching and Plant Spacing on Growth, Yield and Quality of Watermelon (Citrullus Lanatus) in Rapti Riverbed, Dang, Nepal

A field experiment was conducted at Rapti riverbed, Dang, Nepal to study the effects of mulching and plant spacing on growth, yield, and fruit quality of Mastana- a hybrid cultivar of watermelon- during February-May 2019. The two-factor experiment had three types of mulching- black silver polythene, rice straw, and control (no mulch), and three different plants spacing- 2m×1m, 2m×1.5m, and 2m×2m. The experiment was laid out in randomized complete block design with three replications. The result showed both mulching and plant spacing significantly influence growth, yield and quality of watermelon. Considering the mulching materials, the minimum days required for germination (14.44 days), the longest main vine length (316 cm), maximum number of leaves per plant (99.42), the highest individual fruit weight (7.30 kg) and fruit yield mt ha-1 (122.1), the maximum TSS and vitamin C content (12.11°B and 18.76 mg/100 g) were recorded from the plants grown under black silver polythene mulch and the lowest values were recorded from the plants grown without mulching except days required to germination and titratable acidity. In case of plant spacing, the higher yield was recorded in 2m×1m plant spacing (140.3 mt ha-1) as compared to 2m×1.5m (95.5 mt ha-1) and 2m×2m (75.2 mt ha-1). Likewise, effect of plant spacing on the number of leaves plant-1 was significant in 40 DAS, and 80 DAS. Therefore, Mastana, a hybrid cultivar of watermelon is recommended to grow on black silver polythene with 2m×1m plant spacing in Rapti Riverbed conditions. SAARC J. Agric., 21(2): 41-52 (2023)

Development of a model to study visual categorization learning in chickens (<i>Gallus gallus domesticus</i>)

Categorization is a cognitive process that enables individuals to recognize similar yet distinct stimuli as equivalent [1–3]. To categorize an object, agents must identify key features of the new object by applying what they have learned from previous interactions with objects in that category [4]. Thus, categorization eliminates the need for the agent to repeatedly investigate each new object, thereby significantly expanding its adaptive capabilities. However, the nervous mechanisms that regulate this process are still not well understood. The primary aim of the present study is to establish an experimental behavioral model that will facilitate the investigation of the neurobiological mechanisms underlying visual categorization learning. Chickens (Gallus gallus domesticus) were selected as a visual learning model. The study of categorization used the chickens’ innate tendency to peck at new small objects and remember their characteristics. For this purpose, a chick was placed in a cage that resembled a house cage with beads affixed to the floor. The “bead floor” consisted of more than 100 beads of different colors and food scattered throughout [5]. In the developed model, pecking solely on the beads was deemed inaccurate as opposed to pecking on the food. For training purposes, the chick was given 80 peckings and evaluated based on how many nibbles it used to create categories for “beads” vs. “food”. If the chick did not make at least 5 cues or was unable to make 80 cues within 10 minutes during the training session, it was excluded from the study. First, the study investigated the effect of simultaneously presenting two new categories of “food” and “beads” on chicks’ behavior. The group that formed both “beads” and “new food” categories made more errors during the learning period, but performed as well as the group that only formed the “bead” category during the subsequent test. The study analyzed whether chicks could categorize objects (beads) of different sizes into a unified group. The chicks were trained with a floor of small beads and later tested with a different floor of larger beads. Results revealed that the chicks did not transfer their categorization ability from small to large beads. In the opposite scenario, where the chicks were presented with large beads during their training, and then offered small beads during the test, they refrained from pecking the smaller ones. In the next stage, we examined how the object’s color affected the development of a novel category. The results showed that when the chicks were presented with the floor containing an additional color of beads, specifically yellow, they made the majority of errors while pecking the “new type of beads”. Then, the study evaluated whether the chicks could transition the classification of “beads” between color set № 1 (blue, pink, green, yellow, and black silver) and color set № 2 (light green, beige, blue, red, gold, and white), and vice versa. The findings indicate that the chickens do form the categories of “beads” in both versions of the task, and after training, do not peck at beads of the new color. Chickens are capable of categorizing “beads” and “food”, and can generalize within these categories. Thus, this experimental study established the formation of categories in chickens during fast learning. Future application of the model will enable the investigation of the underlying neurobiological mechanisms in categorization learning.

Susceptibility to certain types of scab in the Karelia’s conditions

The article presents the results of a three-year field experiment to study potato yields, as well as the incidence of Kholmogorsky (early ripening) and Nevsky (middle early) varieties with black scurf and silver scurf when planting visually infection-free seed tubers with varying degrees of growth cracks. Tuber cracking can be caused by abiotic, biological and anthropogenic factors. Tuber cracking leads to a decrease in the marketability, an increase in waste during mechanical peeling of potatoes, an increase in the likelihood of its infection with pathogens. It was found that the maximum shortage of the crop was detected with the greatest degree of fracturing of the seed material. The use of tubers with such a defect for planting caused a 1.1-fold decrease in the yield of the studied varieties relative to the controls - without growth cracks. With the intensification of the development of functional disease on potatoes, the prevalence of black scurf increased (by 8.3) and silver scurf (7.6%), especially in the early-maturing Kholmogorsky variety.

Food Preferences in Two Detritivore Species: Laboratory Choice Tests Using Leaf Litters of Different Tree Species

Soil fauna, including terrestrial isopods, millipedes and earthworms, play an important role in the decomposition of litter through the process of shredding it during consumption. In the present study, the food preferences in two detritivores, the common woodlouse (Oniscus asellus) and the earthworm (Lumbricus rubellus) over the leaf litter of four common tree species: common black alder (Alnus glutinosa), silver birch (Betula pendula), small-leaved linden (Tilia cordata) and pedunculate oak (Quercus robur) were quantified in the laboratory. For each animal species, two sets of feeding mesocosms were prepared: one set with single litter species and another with mixed litter material (cafeteria-type test), where the animals were allowed to choose among the four litter species at once. The food preferences of the studied animals were determined on the basis of the consumption (mass loss) of litter for each litter species at the end of two-weeks lasting experiments. The results showed that the litter mass losses in both detritivores were significantly influenced by the tree species. The litter mass losses can be ranked in descending order as follows: alder, birch, linden, oak. In the case of O. asellus, litter mixing had no effect on litter mass loss when compared to single alder and birch litter, however mixing clearly accelerated litter mass loss compared to single lime or oak litter. For L. rubellus, litter mixing was found to slow litter mass loss compared to each single alder, birch and lime litter, while accelerating litter mass loss compared to single oak litter. For the interpretation of the results, the literature data on carbon to nitrogen ratio, as well as the proportion of difficult-to-degrade polyphenols and lignins in leaves of the studied tree species were used.

Thermosensitive black phosphorus hydrogel loaded with silver sulfadiazine promotes skin wound healing

Wounds can lead to skin and soft tissue damage and their improper management may lead to the growth of pathogenic bacteria at the site of injury. Identifying better ways to promote wound healing is a major unmet need and biomedical materials with the ability to promote wound healing are urgently needed. Here, we report a thermosensitive black phosphorus hydrogel composed of black phosphorus nano-loaded drug silver sulfadiazine (SSD) and chitosan thermosensitive hydrogel for wound healing. The hydrogel has temperature-sensitive properties and enables the continuous release of SSD under near-infrared irradiation to achieve synergistic photothermal and antibacterial treatment. Additionally, it exerts antibacterial effects on Staphylococcus aureus. In a rat skin injury model, it promotes collagen deposition, boosts neovascularization, and suppresses inflammatory markers. In summary, the excellent thermosensitivity, biocompatibility, and wound-healing-promoting qualities of the reported thermosensitive hydrogel make it suitable as an ideal wound dressing in the clinic.

Growth and production of garlic (Allium sativum L.) in the lowland on various types of mulch

This study aims to determine the effect of mulch treatment on the growth and production of garlic (Allium sativum L.) in the lowlands. The research was conducted in Lempong Village, Bola District, Wajo Regency located 78 m above sea level (asl) with an average temperature of 24ºC - 33ºC. This research was set using a Split Plot Design (SPD) with garlic varieties set as the main plots consisting of highland (var. Lumbu Hijau) and lowland varieties (var. Lumbu Putih) while mulch types were set as subplots consisting of control (no mulch), black silver plastic mulch, rice straw mulch, Gliricidia (Gliricidia sepium) leaves mulch, and banana leaves mixed with stem mulch. Each treatment combination was repeated 3 times. The results show that the Lumbu Putih variety had better growth and production than the Lumbu Hijau on the parameters of plant height, number of leaves, and number cloves per tuber. Straw mulch showed the best effect in suppressing soil temperature (28.5ºC). Banana leaves and stem mulch was the best type of mulch compared to control and other mulches on parameters of plant height, number of leaves, and number of cloves per tuber. The interaction between the Lumbu Putih variety and banana leaf and stem mulch produced the highest production per hectare (1.6 ton ha−1).

Vulcanization failure mechanism analysis of lead-frame LED package

Light-emitting diodes (LED) failure can be attributed to various factors such as vulcanization, which is considered as one of the primary causes. The main consequence of vulcanization is the production of black silver sulfide, a result of silver and sulfur ion interaction within the plating layer. The consequences of this reaction can be quite severe, leading to a reduction in luminous flux, color temperature drift, golden ball and support fracture. In this work, following an analysis of the process structure characteristics of LED support, four vulcanization failure paths have been identified. To determine the main vulcanization path of the LED stent, various tests, such as the vulcanization corrosion test, the red ink test, and the cross-section test, have been conducted. This work provides an innovative and constructive approach for directing failure research in LED package.

The Effect of Various Kinds of Mulch on the Growth and Production of Chili Plants

This study aims to determine the effect of mulching on the growth and production of chili plants. This study used a randomized block design, with 6 treatments and 4 replications. One treatment 4 sample plants. The treatments used are as follows: M0: Without using mulch; M1= Using reed mulch; M2 = Using rice straw mulch; M3 = Use silver black plastic mulch; M4 = Using clear plastic mulch; M5 = Use clear mulch covered with newspaper. The variables observed were plant height, number of secondary branches, fruit weight per plant, dry plant weight and production per hectare. Based on the results of the research that has been carried out, it was concluded that: black silver plastic mulch treatment gave the best effect on the growth and production of chili plants, such as plant height, number of secondary branches, fruit weight of each plant, dry weight of plant trunks, and production per hectare. Meanwhile, the production of red chilies per hectare produced by silver black plastic mulch has a higher capacity of 8.02 tons/ha and the lowest yield is 3.01 tons/ha of clear plastic mulch.

PENGARUH PEMBERIAN MULSA DAN BEBERAPA JENIS PUPUK DAUN TERHADAP PERTUMBUHAN DAN HASIL TANAMAN TERUNG (Solanum melongena L.)

Eggplant is a type of vegetable that is used as an ingredient in vegetables or fresh vegetables. The nutritional content of eggplant is very high, especially the content of vitamin A and phosphorus. However, eggplant productivity has decreased along with the lack of nutrients absorbed. Therefore, mulch and foliar fertilizer are the right innovations to be applied to support the eggplant. The existence of mulch to suppress the growth of weeds and the availability of nutrients N, P, and K in the soil. The purpose of this study was to determine the application of mulch and foliar fertilizer to the growth and production of eggplant plants. This research was conducted in Banjarejo Village, Kedungpring District, Lamongan Regency. This study used a Randomized Block Design (RAK) with a factorial pattern with 3 replications, consisting of 2 factors, namely: type of mulch (M) and leaf fertilizer (D). The first factor consisted of 3 types of mulch, namely: no mulch (M0), straw mulch (M1) and silver black plastic mulch (M2). The second factor of foliar fertilizer consisted of 3 levels, namely: growmore foliar fertilizer (D1), mamigro foliar fertilizer (D2), and gandasil D (M3) leaf fertilizer. Based on the results of the study, it was concluded that the application of mulch and foliar fertilizers on the growth and production of eggplant plants had an interaction between the treatment of mulch and foliar fertilizers on plant height (42 DAP), fruit diameter, plant weight, and fruit weight per hectare at the age of 77 DAP. The application of black silver plastic mulch and mamigro leaf fertilizer got the best results on the parameters of plant height, fruit diameter, plant weight and fruit weight per hectare.

Evaluation of Mulching Methods and Legume Intercropping on Weed Control Efficiency and Agronomic Traits of Pearl Millet (Pennisetum glaucum)

Aim: To evaluate the weed control efficiencies of different mulching practices and legume intercropping in transplanted pearl millet.
 Study Design: Randomized Complete Block Design (RBD).
 Place and Duration of Study: The field trial was conducted during the Rabi season of 2022 at the school of agricultural sciences in Karunya Institute of technology and sciences, Coimbatore, Tamil Nadu.
 Methodology: The field trial consists of 8 treatments viz., T1 - PE of Atrazine 0.5kg/ ha +1 Hand Weeding at 30 DAT, T2 - Two Hand Weeding at 15 and 30 DAT, T3 - Paddy straw mulching at 5t/ ha 3 DAT, T4 - Black polythene mulching at 3 DAT, T5 - Black silver polythene mulching at 3 DAT, T6 - Intercropping of pulses (cowpea) (1:1), T7 - Intercropping of pulses (cowpea) (1:1) + PE Pendimethalin 0.75 kg/ ha, T8 - Un weeded check.
 Results: Results of the experiment proves that the intercropping of cowpea in pearl millet along with the pre-emergence application of pendimethalin proves to be beneficial and advantageous in terms of returns per rupee invested for profitable crop production, rather than going for polythene mulches. Hence adoption of legume intercropping in pearl millet, along with the usage of mild herbicides like pendimethalin, will be an economically viable and environmentally sustainable weed management practice for improving the yield of pearl millet.

Stability of Silver and Fluoride Contents in Silver Diamine Fluoride Solutions

ObjectiveThis study aims to determine the stability, alkalinity, and fluoride and silver ion concentrations of 5 commercially available 38% silver diamine fluoride (SDF) solutions—namely Advantage Arrest, e-SDF, Riva Star, Saforide, and Topamine—in 180 days. MethodsAlkalinity was determined using a pH electrode. The fluoride and silver ion concentrations were obtained using a calibrated ion-selective electrode and optical emission spectrometer, respectively. Six bottles of each product were examined on days 0 (freshly opened), 30, 60, 90, and 180. The time taken for each freshly opened product to form a black silver precipitate under room light (500 lx) and 25 °C was also recorded. ResultsFor 180 days, Advantage Arrest, e-SDF, Riva Star, Saforide, and Topamine had the pH range of 9.8–9.8, 10.5–10.6, 13.0–13.1, 9.8–9.8, and 9.3–9.4; fluoride ion concentration range (nearest 1000 ppm) of 40.9%–42.4%, 46.7%–50.9%, 37.0%–39.0%, 37.0%–45.7%, and 47.7%–53.4%; silver ion concentration range (nearest 1000 ppm) of 283.4–307.0, 307.3–315.4, 418.6–435.7, 266.3–281.0, and 416.2–456.1 ppm; and precipitation time (nearest hour) of 17, 12, 6, 7, and 7 hours, respectively. The percentage change of fluoride and silver could be more than 5% after 60 days. ConclusionsThe alkalinity of the 5 SDF solutions remained stable after 180 days. In addition, their fluoride and silver concentrations decreased substantially after 60 days. The freshly opened SDF solutions did not precipitate within 5 hours under ambient room conditions. The alkalinity and fluoride and silver concentrations of the 38% SDF solutions could be less stable after 60 days; thereafter, the fluoride and silver concentrations decreased. Thus, the SDF solution should be used within 60 days after opening.

Response of Long Bean Vegetative Growth Due to Different Types of Mulch and Doses of Vermicompost

Long beans are plants of the Leguminoceae family that grow on vines. Long bean growth rate is influenced by various factors. Some of the external factors that determine the growth rate of long beans are the availability of nutrients and the application of mulch on agricultural land. Research on the vegetative growth response of long bean due to different types of mulch and doses of vermicompost fertilizer has been carried out in Mertak Umbak Village, Central Lombok. This study aims to analyze: (1) the vegetative growth response of long bean due to different types of mulch, (2) the vegetative growth response of long bean due to different doses of vermicompost, (3) the effect of a combination of types of mulch and vermicompost dosage on long bean growth. Research data were analyzed using Anova. The research results show that: (1) the vermicompost treatment significantly affected the increase in total leaf and plant height, but did not have a significant effect on the length and width of long bean leaves, (2) the application of mulch had a significant effect on all observed growth parameters, the highest growth parameters were observed in the application of plastic mulch black silver, (3) the interaction of mulch type and vermicompost dosage had a significant effect on plant height but did not have a significant effect on other growth parameters.

The Black Death and Consequences for Labor

Abstract From the perspective of the Black Death, the economic consequences for laborers in our unfolding pandemic, COVID-19, might come as a surprise. Instead of labor shortages benefiting workers, especially the unskilled, and narrowing the gap between rich and poor, our pandemic has sent economic inequality racing forward across the world with laborers’ health and material well-being plummeting. However, a closer examination of the Black Death suggests that the consequences for labor of the two pandemics may not be as different as first assumed. This essay explores the silver lining for labor after the dramatic crash in population caused by the Black Death and subsequent waves of plague during the second half of the fourteenth century. By first turning to Europe as a whole and then concentrating on Italy, this essay challenges notions that labor conditions and standards of living improved immediately after the Black Death's halving of populations and that these changes were almost universal across Europe or even within city-states, such as Florence, or in rural areas hosting different sorts of agricultural workers. In Italy, where real wages have been calculated, the Black Death's silver lining for laborers failed to arrive until two or three generations after 1348. Moreover, compressing economic inequality from the late fourteenth to the late fifteenth centuries spurred reactions from elites that wrought new inequalities in other spheres of activity.