Measurement of tissue oxygen saturation levels using portable near‐infrared spectroscopy in clinically healthy dogs

Objective – To establish a reference interval for tissue oxygen saturation (StO₂) levels measured by a portable near‐infrared spectroscope and determine site(s) for reproducibly measuring StO₂ levels in dogs. Design – Prospective experimental study. Setting – Veterinary teaching hospital. Animals – Seventy‐eight healthy dogs. Measurements and Main Results – A portable device that quantitatively measures StO₂ levels directly in muscle tissue using near‐infrared spectroscopy (NIRS) was topically applied to shaved sites over 4 muscle bodies. Readings from the sartorius muscle were obtained 100% of the time. The digital extensors and biceps femoris muscles provided similar readings, but less consistently obtained StO₂ values (70% and 67%, respectively). Mean StO₂ levels measured over these 3 sites were not statistically different from one another. When readings from these 3 sites were combined, a mean ±1 SD of 92.9±7.4% was obtained. The epaxial muscles produced a significantly lower mean ±1 SD (68.5±22.4%), and readings were obtained only 60% of the time. Conclusions – In dogs, a mean ±1 SD of 92.9±7.4% can be used to investigate clinical applications of NIRS. The sartorius muscle most consistently allows for detection of StO₂ levels (100%). The epaxial muscles are not consistent or reliable for obtaining StO₂ readings and are not recommended for clinical application of near‐infrared spectroscope. Sex does not significantly affect StO₂ readings at any site. Body condition score only affects readings obtained from the sartorius muscle.     

Introgression of a Tombusvirus Resistance Locus from Nicotiana edwardsonii var. Columbia to N. clevelandii

ABSTRACT A new variety of Nicotiana, N. edwardsonii var. Columbia, was evaluated for its capacity to serve as a new source for virus resistance genes. Columbia was developed from a hybridization between N. glutinosa and N. clevelandii, the same parents used for the formation of the original N. edwardsonii. However, in contrast to the original N. edwardsonii, crosses between Columbia and either of its parents are fertile. Thus, the inheritance of virus resistance genes present in N. glutinosa could be characterized by using Columbia as a bridge plant in crosses with the susceptible parent, N. clevelandii. To determine how virus resistance genes would segregate in interspecific crosses between Columbia and N. clevelandii, we followed the fate of the N gene, a single dominant gene that specifies resistance to Tobacco mosaic virus (TMV). Our genetic evidence indicated that the entire chromosome containing the N gene was introgressed into N. clevelandii to create an addition line, designated N. clevelandii line 19. Although line 19 was homozygous for resistance to TMV, it remained susceptible to Tomato bushy stunt virus (TBSV) and Cauliflower mosaic virus (CaMV) strain W260, indicating that resistance to these viruses must reside on other N. glutinosa chromosomes. We also developed a second addition line, N. clevelandii line 36, which was homozygous for resistance to TBSV. Line 36 was susceptible to TMV and CaMV strain W260, but was resistant to other tombusviruses, including Cucumber necrosis virus, Cymbidium ringspot virus, Lettuce necrotic stunt virus, and Carnation Italian ringspot virus.     

基于驻波率原理的农药雾滴沉积量检测系统设计与试验

为实现施药后雾滴地面沉积量的快速获取,该文提出一种基于驻波率原理的叉指型雾滴采集极板结构。为验证该极板结构的合理性,应用三维电磁仿真软件HFSS对此系统进行电磁仿真。HFSS模型求解的结果表明,叉指型极板内部出现了静电屏蔽,极板间通过雾滴能够实现电磁耦合,可用于雾滴沉积量检测,系统灵敏程度将随着极板间距的增大而减小。通过标定试验,建立了检测系统输出电压与试剂溶液沉积量关系的回归方程,测试后2种不同介电常数的胭脂红溶液和丙三醇溶液决定系数R2分别为0.982 1和0.997 6。通过对3W-ZW10型温室自走式喷雾机应用测试,结果表明:该系统在采样点上沉积量的模拟值最大相对误差率不超过7.95%,且模拟值与实测值均方根误差RMSE最大为0.076 7 mg/cm~2,雾滴沉积检测准确率高,方便实用,可用于田间雾滴沉积率的快速测量。     

Short-Term Impacts of Pecan Waste By-Products on Soil Quality in Texturally Different Arid Soils

Three arid soils (clay loam (CL), sandy clay (SC), and sandy loam (SL)) were amended with pecan waste products (ground pecan shells (PSHs), ground pecan husks (PHUs), and ground pecan shell biochar (PSB)), at a rate of 45 Mg/ha, packed inside cylindrical rings and kept in a humid chamber for 4 weeks. Measurements taken included volumetric moisture content as the soil dried out for 7 days, wet aggregate stability (WAS), permanganate oxidizable carbon (POXC), nitrate-nitrogen, extractable phosphorus (Olsen-P), and water-extractable potassium (K). Significant effects of soil texture, soil amendment, and their interaction were observed for all measurements. Generally, the amendments led to significant improvement in Olsen-P, K, POXC, and WAS, while amendments’ impacts on soils of different textures varied. Short-term moisture retention was dependent on soil texture, with PHU and PSB treatments having higher soil moisture retention in SL and CL soils but not in SC soil.     

Deep time: the emerging role of archaeology in landscape ecology

Given the goals of landscape ecology, information from archaeological sites provides a useful source of evidence regarding cultural practices, anthropogenic change, local conditions, and distributions of organisms at a variety of scales across both space and time. Due to the time depth available from the archaeological record, long-term processes can be studied and issues of land use legacies, human influence on landscape heterogeneity, and system histories can be addressed. Archaeological data can produce a diachronic record of past population size, population structure, biogeography, age-at-death, and migration patterns, useful for making ecosystem and wildlife management decisions. Researchers can use archaeological knowledge to differentiate between native and alien taxa, inform restoration plans, identify sustainable harvesting practices, account for modern distributions of taxa, predict future biogeographic changes, and elucidate the interplay of long- and short-term ecological processes.