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The studies were carried out during 2020-2021 on ewes (515 heads) of the Kharkiv intrabreed type of the Prekos breed (KhTP) and their offspring in the conditions of the breeding plant of the State Enterprise of the Experimental Farm Gontarovka of the Institute of Animal Sciencе of the National Academy of Sciences of Ukraine. It was established that for 45 days during artificial insemination, the fertility of sheep (OP), calculated according to the results of their lambing, averaged 91.8 %. The highest rate was characterized by sheep that had the third lamb - 97.3 %. According to the results of 4-6 lambs, a relatively stable high fertility of queens was noted - 93.4-95.3 %. Significant downward deviations of this indicator were observed in ewes used for reproduction in the first and second years, and especially in animals with 7 and 8 or more lambing. Analysis of variance found that the age factor of ewes is highly likely (p

Biological activity of the soil is an indicator characterizing the number of organisms living in the soil, and quantitatively evaluating the results of their vital activity. High biological activity is a factor in increasing soil fertility and its phytosanitary state, achieved by creating optimal living conditions for soil microorganisms: providing nutrients, especially organic matter, moisture, heat and soil aeration. In this paper, we assess the effect of hydrogels of different chemical bases on the microbiological activity of sod-podzolic sandy loam soil. The effect of hydrogels on the microbiological activity of sod-podzolic soil was studied in a microfield experiment in a special installation (“dry place”) under conditions of soil drought and field conditions (Menkovsky branch of the FSBIU API, Gatchinsky district, Leningrad region). The experience was laid with two types of hydrogels (potassium and sodium base) with a single dose (40 g/m2). In the experiment, the indicators of soil biological activity were compared in the following variants: soil - control with the addition of 90 kg ha-1 NPK in the form of an azofoska, hydrogel introduced to a depth of 10–12 cm + N90 P90 K90, hydrogel introduced to a depth of 20–22 cm + N90P90K90. Samples of sod-podzolic sandy loam soil were taken from depths (10–12 cm and 20–22 cm) at the beginning and at the end of the growing season. In the course of the studies, it was found that when the hydrogel is introduced, both in the upper root-inhabited soil layer and in the 20–22 cm layer, favorable conditions are created for the microbiological activity of sod-podzolic sandy loam soil. It has been established that the chemical basis of the hydrogel does not inhibit the activity of the microbial community.

Collateral legal relations are an important factor of the investment process development. They reduce opportunistic loan risks and increase partners’ confidence within the transaction. The mortgage fund of Nizhniy Novgorod region is nowadays involved in the implementation of investment and innovation projects up to 70%. Although the institutional environment of regional collateral relation has drastically improved in the last 11 years, the current status is far away from the ideal. Imperfect legal framework of collateral legal relations with the public property leads not only to information asymmetry, but also to a reduced states’ income from these transactions. The paper analyzes the current legislative pledge of state property, describes the main steps of its modernization, identifies the positive aspects and trends, as well as deficiencies, provides and gives a proof of necessary legal framework changes aimed at collateral financial relations efficiency improvement in the region.

A modeling method and structure and type of mathematical models intended for solving problems of managing perennial grass cultivation technologies are proposed.

InAsSb/InAsSbP double heterostructure diode lasers for the spectral range of 3–4 μm grown by liquid phase epitaxy have been investigated. The laser tuning was studied as a function of the stripe width. The temperature and current tuning of such lasers was measured. Emission spectra, far-field patterns and wavelength tuning versus current have been studied in the wide current range from threshold, I th , up to 6 I th at liquid nitrogen temperature. Current wavelength tuning in single-mode lasing has been obtained both towards the shorter wavelengths (up to 4.56 cm −1 ) and towards the longer wavelengths (up to 0.9 cm −1 ) at the temperature T = 77 K. Comparison of the emission properties of the lasers, driven by different types of current pulses showed the same quantum-mechanical nature of current tuning. The theoretical model of this nonlinear optical phenomenon is proposed. The estimated times of current tuning defined mainly by the photon lifetime in the cavity are about 10 −9 to 10 −12 s. The emission line-width was determined to be 20 MHz. Optimal conditions were found for the use of the lasers and were employed for the detection of NH 3 , CH 3 Cl, OCS and atmospheric water.

We studied light-emitting diodes (LEDs) based on GaSb-GaInAsSb-GaAlAsSb heterostructures with the emission due to electron transitions from the conduction band to levels of intrinsic double-charged acceptors. Parallelepiped-shaped LEDs with a round or gridlike contact on the surface of the epitaxial layer were studied experimentally and theoretically. The relations describing the current spreading from round and grid contacts are presented. It is shown that grid contacts, in contrast to round ones, provide a uniform distribution of current over the emitting layer. The current density under a grid contact is smaller than under a round one by a factor of 20, which is especially important for long-wavelength (λ≳2 µm) LEDs, in which the contribution of the nonradiative Auger recombination is significant. An emission power of 3.5 mW at 300 mA current is obtained from grid-contact LEDs.

GaSb-based crystals shaped like a stepped pyramid with smoothed steps are obtained. The crystals are intended for the fabrication of light-emitting diodes in which the short-wavelength emission band of a double-charged intrinsic acceptor is transformed into the long-wavelength band without loss in the amount of photons emitted. It is shown experimentally and theoretically that an increase in the ratio of the area of the light-emitting diode crystal to its volume increases the external quantum yield of photons. A yield of 5.1% for the intrinsic acceptor in GaSb is attained.

Physical mechanisms leading to the suppression of instability in the electron-hole plasma under conditions of population inversion and, thus, promoting single-mode lasing and drive-current-controlled tuning were studied; in particular, nonuniform injection and spatial oscillations of laser flux were considered. Transient times typical of current-and heat-aided tuning are measured. The effective time constant is estimated as ∼1 µs for heat-controlled tuning; by contrast, it is at least one order of magnitude shorter for current tuning. The tuning range does not exceed several angstroms and is as wide as 100 A in the case of heat-and current-aided tuning, respectively. A single-mode fast-tunable heterolaser which is capable of operating within the 2.8–3.6 µm wavelength range at 12–120 K and is designed for laser-diode spectroscopy is developed. The results of using the laser for the detection of absorption spectra in OCS, NH3, CH3Cl, CH4, N2O, and H2O vapors are reported.

Emission spectra and the intensity patterns of InAsSbP/InAsSb/InAsSbP-based diode lasers with different cavity lengths and a spectral range of 3–4 μm were studied. It is ascertained experimentally that a 200-to 300-µm-long and 18-µm-wide laser cavity ensures single-mode lasing, during which the wavelengthdecreases with current by about 100 A and the top of the intensity pattern becomes bimodal, thus indicating that there are transverse spatial oscillations of laser flux in the cavity. In a 300-to 500-µm-long cavity, several tens of modes are generated mainly on the long-wavelength side of the mode that prevailed initially at the lasing threshold and spatial oscillations of laser flux are not observed. Single-mode lasing is attained due to the fact that the transverse oscillations of laser flux flatten the dynamic dielectric phase grating, which is usually produced by the interaction between lasing modes, and prevent an increase in amplification on the long-wavelength side of the dominant mode.

Our earlier reports concerning the fabrication by liquid-phase epitaxy and investigation of InAsSbP/InAsSb/InAsSbP double heterostructure lasers emitting at 3–4 µm are reviewed. The dependences of spectral characteristics and the spatial distribution of the laser emission on temperature and current are discussed. Lasing modes are shifted by 0.5–1.0 cm−1 to longer wavelengths with increasing temperature. The tuning of the lasing modes by means of current is very fast (10−8–10−12 s). With increasing current, the modes are shifted to shorter wavelengths by 50–60 A at 77 K. The maximum mode shift of 104 A (10 cm−1) is observed at 62 K. The spectral line width of the laser is as narrow as 10 MHz. Abnormally narrow directional patterns in the p-n junction plane are observed in some cases in the spatial distribution of laser emission. The current tuning of lasers, due to nonlinear optical effects, has been modeled mathematically in good agreement with the experiment. Transmittance spectra of OCS, NH3, H2O, CH3Cl, and N2O gases were recorded using current-tuned lasers.

Previous publications concerned with the development and investigation of InAsSb/InAsSbP double heterostructure lasers emitting at 3–4 µm fabricated by liquid phase epitaxy are reviewed. In pulsed mode, the maximum operating temperature of the lasers is 203 K, the characteristic temperature is 35 K, and differential quantum efficiency is 20±5% at 77K. Mesa-stripe lasers with a 10-to 30-µm stripe width and a 200-to 500-µm cavity length can operate in CW mode up to 110 K. The total optical output power of more than 10 mW at λ=3.6 µm is obtained at T=82 K in CW mode. The output power per mode does not exceed 2 mW/facet. A single-mode lasing is achieved in the temperature range of 12–90 K.

InAsSb/InAsSbP double heterostructure diode lasers for the spectral range of 3.3 μm grown by liquid phase epitaxy have been investigated. Emission spectra, far-field patterns and wavelength tuning versus current have been studied in the wide current range from threshold value I th up to 3 I th , at the temperature of liquid nitrogen. Controlled by current wavelength tuning in single-mode lasing has been obtained both towards the shorter wavelengths (up to 4.56 cm −1 ) and towards the longer wavelengths (up to 0.9 cm −1 ) at the temperature T =77 K. Comparison of the emission properties of the lasers, driven by different types of current (short pulse current, sawtooth pulse current and in quasi cw regime) showed the same quantum-mechanical nature of current tuning. The theoretical model of this nonlinear optical phenomenon is proposed. The estimated times of current tuning defined mainly by the photon lifetime in the cavity are about 10 −9 –10 −12 s.

A reduction in the emission wavelength in the preferred mode of InAsSbP/InAsSb/InAsSbP heterostructure lasers by 50A is observed when the current is raised from 1.8 to 5 times the threshold with dc and pulsed power. A comparison of the spectral and spatial distributions of the output as functions of current shows that this short-wavelength tuning is caused by a change in the distribution of the nonequilibrium charge carrier concentration over the strip width as the current is varied. This effect is modeled mathematically, taking into account the increase in the injection density and the drop in the output intensity from the middle to the sides of the waveguide. The results of the model calculation are in good agreement with experiment.

Anomalously narrow, single-lobe and double-lobe beam directivity patterns in the plane of the p-n junction have been observed in lasers constructed from InAsSb/InAsSbP heterojunctions emitting at a wavelength of approximately 3.3 µm. Theoretical near-field and far-field radiation distributions for the laser emission of two beams oscillating across the stripe are obtained on the basis of new concepts of the lasing processes. The single-lobe directivity pattern is obtained for the emission of in-phase beams, and the double lobe is obtained for antiphase beams. Correspondence of the theory with experiment is established.

Light-emitting diodes (LED’s) operating in the spectral range 1.9–2.1 µm have been fabricated by liquid-phase epitaxy on the basis of AlGaAsSb/GaInAsSb double heterostructures with a high Al (64%) content in the wide-gap regions. The design of the LED makes it possible to locate the active region near the heat-removal elements of the housing, and pass the light through the GaSb substrate, which is completely unshielded by the contact. The LED’s are investigated in the quasi-continuous (CW) regime and pulsed regime at room temperature. The optical power of the LED’s possesses a linear current dependence over a wide range of currents. A CW optical power as high as 4.6 mW and a peak optical power of 190 mW in the pulsed regime were achieved at room temperature. It is shown that the transition from linear to sublinear current dependence of the optical power is governed by Auger recombination in the pulsed regime at pulse durations as low as 5 µs.

A study has been made of wavelength tuning in double heterostructure InAsSb/InAsSbP-based diode lasers. A simple mathematical model, which takes into account the spatially homogeneous injection and the dependence of the dielectric constant on the charge carrier density, is discussed. The wavelength can be increased or decreased, depending on the pump current and diode structure parameters, as is observed experimentally. The process of wavelength tuning proceeds with virtually zero delay time since it is determined by the photon lifetime in the cavity and in part by the lifetime of nonequilibrium charge carriers.

We have studied the quality of frequency of tuning in a diode laser based on a double heterostructures of the n-InAsSbP/n-InAsSb/p-InAsSbP type driven by short current pulses with positive ramp top. It is established that a monotonic increase in the tuned mode frequency with the time is retained during the first 30-µs-long period of current growth. Then, the dependence of the frequency on the current weakens because of the appearance of nontunable modes. The maximum range of monotonic single-frequency tuning is achieved at a small pulse duration (< 30 μs), which shows prospects for the development of ultrafast-response laser diode spectroscopy.

InAsSb-InAsSbP double heterostructures diode lasers for the spectral region 3.3 /spl mu/m grown by liquid phase epitaxy have been investigated. Emission spectra, far-field patterns and wavelength tuning have been studied over a wide current range from threshold value I/sub th/ up to 3I/sub th/ at the temperature of liquid nitrogen. Current-controlled wavelength tuning has been obtained both towards shorter wavelengths (to 4.56 cm/sup -1/) and towards longer wavelengths (up to 0.9 cm/sup -1/) at a temperature T=77 K, at lasing generation that maintains single mode. Comparison of the emission properties of lasers driven by different types of current (short pulse current, sawtooth pulse current and quasi-CW regime) showed the same quantum-mechanical nature of current tuning. A theoretical model of this nonlinear optical phenomenon is proposed. The estimated times of current tuning, defined mainly by the photon lifetime in the cavity, are about 10/sup -9/-10/sup -12/ s.

The far-zone directional pattern of diode mesastrip lasers with a 10 µm wide strip has been investigated as a function of the current. The directional pattern in the plane of the p-n junction contains one longitudinal mode, whose width depends on the current. It is shown by comparing the theoretically computed and experimentally measured spatial modes that this dependence is determined by the variation of the light flux intensity and the free-carrier density distributions over the strip width as a function of the current. In the case when the distributions are close to uniform the maximum narrow spatial longitudinal mode and a unimodal radiation spectrum are observed.

We have produced, by using liquid-phase epitaxy, 2.7 to 3.0-µm lasers based on InAsSbP double-heterostructures with different phosphorus contents in the active and wide-gap regions. The lasers possess threshold current density ∼0.8 kA/cm2 at 77 K and operate in the pulsed mode up to ∼124 K with maximum threshold current density 10–12 kA/cm2. The lasers have a low series resistance ∼0.45 Ω.

Diode lasers based on InAsSb/InAsSbP with separate electrical and optical confinement, emitting in the wavelength interval 3–4 µm, are investigated. The lasers attain a higher operating temperature when electrical confinement is created by means of type-II heterojunctions. Interface Auger recombination is suppressed in lasers of this type, and the experimental current density is close to the theoretically calculated value for the case of predominant volume Auger recombination at a temperature of 180–220 K.

On the basis of the InAsSb/InAsSbP double heterostructure, lasers with a thick active region (3 µm) and a wide cavity (40 µm) were fabricated that operated near 3.3 µm and were intended for obtaining a low radiation divergence in the p-n-junction plane. Laser emission spectra and radiation patterns for different cur-rents were studied. The current-induced shift of the laser emission line reaches 24 A. The half-width of the radiation pattern is 9° in the p-n-junction plane and 63° in the perpendicular plane. The experimental data on the radiation pattern are compared with the theoretical results expected in the case where two in-phase waves with the same amplitude are formed in a cavity.

The lasing spectra and the shift in the position of the modes in the current range (1–5)I th with various methods of pumping the nonequilibrium charge carriers are analyzed. It is shown that the pumping method does not influence the character of the tuning of the radiation line. The large short-wavelength tuning range (up to 50 A) is due not to the heating of the crystal lattice in the active-region material but rather the nonuniform nonequilibrium charge-carrier density distribution over the width of the stripe.

AlGaAsSb lasers with different Al concentrations in the active and confinement regions are fabricated and investigated. The structures lase in the region ∼1.6 μm. The AlGaAsSb solid solution in the active region is a direct-gap material with a small energy separation (∼56 meV) between the direct-gap Γ minimum and the indirect-gap L minimum of the conduction band. The lasers have a single-mode spectrum with a predominant longitudinal mode in the spatial distribution of the emission. The lasers operate at room temperature in a pulsed mode.

The striking increase in the use of nitrogen (N) and phosphorus (P) fertilizers between 1960 and 2000 by intensive agricultural practices has led to degradation of air and water quality (Tilman et al., 2001). However, the existence of common legume plant genes that are implicated in both nitrogen-fixing and arbuscular mycorrhizal symbioses – the two associations that improve mineral nutrition, water supply and tolerance to biotic and abiotic stresses of plants – poses the question of how such a tripartite symbiosis (legume plant + arbuscular mycorrhizal fungi + nodule bacteria) can be exploited in sustainable agriculture (Borisov et al., 2004). The great genetic variability shown in the effectiveness of such a system for pea (and, obviously, for other legumes) clearly demonstrates that we can and should breed legumes to increase the symbiotic potential of the tripartite symbioses (Jacobi et al., 2000).

An investigation was made of continuous tuning of the emission wavelength in two types of InAsSb/InAsSbP diode heterolasers: three-layer structures with combined electrical and optical confinement and five-layer structures with separate confinement. In three-layer structures the emission wavelength initially decreases by 2–4 A with increasing current and then increases by 10–15 A. In five-layer structures the emission wavelength mainly decreases. This difference is attributed to the better flow of carriers in the bulk of the active region in five-layer structures as compared with three-layer ones.

InAsSb/InAsSbP double heterostructure diode lasers for the spectral range of 3-4 microm grown by liquid phase epitaxy have been investigated. The laser tuning was studied as a function of the stripe width. The temperature and current tuning of such lasers was measured. Emission spectra, far-field patterns and wavelength tuning versus current have been studied in the wide current range from threshold, Ith, up to 6Ith at liquid nitrogen temperature. Current wavelength tuning in single-mode lasing has been obtained both towards the shorter wavelengths (up to 4.56 cm-1) and towards the longer wavelengths (up to 0.9 cm-1) at the temperature T=77K. Comparison of the emission properties of the lasers, driven by different types of current pulses showed the same quantum-mechanical nature of current tuning. The theoretical model of this nonlinear optical phenomenon is proposed. The estimated times of current tuning defined mainly by the photon lifetime in the cavity are about 10(-9) to 10(-12) s. The emission line-width was determined to be 20 MHz. Optimal conditions were found for the use of the lasers and were employed for the detection of NH3, CH3Cl, OCS and atmospheric water.

The available publications concerned with fabrication and study of light-emitting diodes (LEDs) intended for operation in the 1.6–4.4 μm spectral range; based on GaSb substrates; and grown by liquid-phase epitaxy, which makes it possible to form fairly thick layers lattice-matched to GaSb, are reviewed. In these studies, the active region consists of the GaInAsSb compound in LEDs for the spectral ranges 1.8–2.4 and 3.4–4.4 μm and the AlGaAsSb compound for the spectral region 1.6–1.8 μm. The wide-gap AlGaAsSb confining layers contain up to 64% of Al, which is an unprecedentedly high content for liquid-phase epitaxy. Asymmetric (GaSb/GaInAsSb/AlGaAsSb) and symmetric (AlGaAsSb/GaInAsSb/AlGaAsSb) heterostructures have been fabricated and studied. Various types of designs that make it possible to improve the yield of radiation generated in the active region have been developed. The measured external quantum yield of emission is as high as 6.0% at 300 K for the LEDs operating at the wavelengths 1.9–2.2 μm. A pulsed optical-radiation power of 7 mW at a current of 300 mA with a duty factor of 0.5 and 190 mW at a current of 1.4 A with a duty factor of 0.005 have been obtained. The external quantum emission yield of ∼1% has been obtained for LEDs that emit in the spectral range 3.4–4.4 μm; this yield exceeds that obtained for the known InAsSb/InAsSbP heterostructure grown on an InAs substrate by a factor of 3. The measured lifetime of minority charge carriers (5–0 ns) is close to the theoretical lifetime if only the radiative recombination and impact CHCC bulk recombination are taken into account. The impact recombination is prevalent at temperatures higher than 200 K for LEDs operating in the spectral range 3.4–4.4 μm and at temperatures higher than 300 K for LEDs operating in the spectral range 1.6–2.4 μm.

Light-emitting diodes (LEDs) with the active region based on Ga1− xInxAsySb1−y solid solutions are obtained on GaSb substrates. The active region has a composition close to the domain of immiscibility (x = 0.24) and a reduced arsenic content (y = 0.16). The diode structures exhibit a high density of misfit dislocations. Nevertheless, the room-temperature external quantum yield reaches a record-high level of 1.2% in the spectral band with a maximum wavelength of 2.42 μm. The maximum output radiation pulse power reaches 3.3 mW at a current of 600 mA. The emission is predominantly due to the interband transitions, which is evidence of a high degree of stoichiometry of the active region.

The therapeutic efficiency of kanamycin and vibromycin in treatment of gonorrhea was studied on 112 and 86 males respectively. Clinical and etiological recovery was observed in 85.6 and 92.9 per cent of the patients. The best therapeutic results were obtained with the use of vibromycin in a course dose of 500 mg. A single administration of the drug in a course dose of 300 mg was less effective. The gonococci disappeared from the urethra secretion under the effects of kanamycin and vibromycin 4-10 hours after beginning of the treatment. The minimum concentration of vibromycin inhibiting the gonococcal growth on nutrient media ranged from 0.02 to 0.4 units/ml.