Length Of Recovery Period Research Articles

Acceptance and willingness of patients with chronic facial nerve palsy for an implantable device that assists with eye closure

Patients with facial nerve palsy often experience lagophthalmos (incomplete eye closure), which can lead to exposure keratitis. The Bionic Lid Implant for Natural Eye Closure (BLINC) is a medical device designed to mimic the morenatural blink kinetics than traditional lid loading techniques. This study aimed to evaluate potential factors that might influence the design of the BLINC device and willingness of participant to undergo the implant placement surgery. Patients attending a multidisciplinary facial nerve clinic were invited to complete a survey addressing patient acceptance of the BLINC device implantation. Seventy-two patients were mailed the survey, of which 50 returned completed surveys (69%). The most important factor identified by participants was the device function (81% ranked as very important) and the least important factor was cost (16% ranked as very important). Median acceptable device function time was 5 years (range 1-10 years). Ten participants (20%) indicated willingness to be the first to trial BLINC. Women were more likely to rate visual appearance as important (OR 3.32, CI 1.14-9.62, p=0.028), and less likely to rate user friendliness as important (OR 0.16, CI 0.04-0.52, p=0.0021). Older participants were more likely to rate the length of recovery period as important (OR 1.04, CI 1.01-1.08, p=0.006). Participants with complete eye closure were less likely to be willing to trial the implant (OR 0.08, CI 0.00-0.53, p = 0.006, whilst patients with eye irritation were more willing to trial the implant (OR 7.20, CI 1.12-142, p = 0.036). Certain patient demographics impact patient aesthetic and functional preferences and the willingness to trial the BLINC device.

#5785 ACUTE KIDNEY INJURY AS A RISK FACTOR FOR THE DEVELOPMENT OF CHRONIC KIDNEY DISEASE AND MORTALITY IN HOSPITALIZED PATIENTS

Abstract Background and Aims Acute kidney injury (AKI) is a complication that affects more than 5% of all hospital admissions and up to one third of patients admitted to critical care units. This entity, whose incidence is on the rise, remains a major cause of morbidity and mortality. In addition, AKI has been linked as an independent risk factor for mortality, especially in severe forms, and of those patients who survive, a percentage will develop chronic kidney disease (CKD) during follow-up. We conducted this study to analyse the incidence of CKD at 6 and 12 months follow-up in hospitalized patients with AKI, to identify possible risk factors leading to its development and to determine mortality in this group of patients. Method This is a retrospective study of a cohort of cases with AKI (baseline eGFR >60 mL/min/1.73 m2 without previous structural damage) from our hospital, taking place from June 2020 to February 2021. Regarding the evolution of the AKI, four possibilities were considered: recovery of normal kidney function, development of CKD at 6 months, development of CKD at 12 months or death during follow-up. Results We studied 148 patients (55% male), with a median age of 83 years (74-87). Thirty-six patients (24.3%) developed CKD at 6 months follow-up and 30 patients (20.3%) at 12 months. Forty-one patients (27.7%) died within the first 12 months following de episode of AKI. The risk factors identified for development of CKD at 12 months were older age (85 vs 77; p = 0.03), higher serum lactate dehydrogenase levels at admission (246 U/L vs 201 U/L; p = 0.04) and at 3 months (252 U/L vs 192,5 U/L; p = 0.039), and eGFR < 60 mL/min/1.73 m2 at 1 week (74,5 vs 57; p = 0.004) and at 3 months (79 vs 50; p < 0.001) of follow-up. Identified risk factors and predictors of AKI-associated mortality were older age (84 vs 80,5; p = 0.018), concomitant oncological pathology (10,8% vs 7,4%; p = 0,018), higher Charlson index (6 vs 5, p <0.001), higher AKI stage (p = 0.042), lower serum albumin levels at first (3.35 g/dL vs 3.90 g/dL; p = 0.014) and at third month (3,2 g/dL vs 4 g/dL; p < 0.001) of follow-up. Conclusion Our study showed a high incidence of CKD in patients who have had an episode of AKI. Several risk factors for development of CKD were identified, being the older age and the greater length of recovery period from AKI the most useful predictors in the clinical practice. AKI-associated mortality was very high in those older patients with higher comorbidity and persistence of AKI. Despite advances, we need non-classical biomarkers for early diagnosis and more effective therapeutic measures to avoid this high prevalence of CKD and mortality.

Uji Ketahanan Galur Jambu Mete Terhadap Hama Helopeltis sp. (Hemiptera: Miridae)

<p><em>One of the causes of low cashew productivity in production centers is the attacks by pest, especially the mosquito bug </em>Helopeltis<em> </em><em>sp. (Hemiptera: Miridae). Control efforts can be done by using the resistant varieties. The study was conducted at Cikampek Experimental Farm, from January–December 2018. This study aims to determine the level of resistance of crossbred cashew (F1) against </em>Helopeltis<em> sp. using the free-choice test method. The study was arranged in a Randomized Group Design and repeated 2 times. Total of 50 crossbred cashew strains propagated by grafting were placed in cages in a circular position. The number of plants in each cage was 23 strains. A total of 5 pairs adult of </em>Helopeltis<em> sp. that had been fed for 2 hours were introduced and placed in the center of the cage. The observation began 2 days after </em>Helopeltis<em> sp. infested which repeated every 3 days for 1 month or stopped if the insects died. Parameters observed included the number of eggs laid, number of eggs hatched, number of </em>Helopeltis<em> sp. perched, attack intensity, number of shoots, number of leaves grown and length of recovery period. The results showed that 23 strains were tolerant to </em>Helopeltis<em> sp., namely numbers: 2.1, 5.3, 6.4, 7.1, 7.3, 8.1, 9.1, 10.3, 11.4, 13.3, 13.4, 14.1, 15.1, 17.1, 18.1, 19.1, 19.3, 21.1, 21.3, 22.3, 22.4, 24.1, and 25.4. The attack intensity was 10-87.5 %. At the time of recovery, shoot growth reached 1-4 shoots and leave growth reached 2-11 leaves. The recovery period occurred for 10-14 days. The yield of the tolerant strains obtained required for further testing in the field.</em></p>

Selected Articles from This Issue

During the COVID-19 pandemic, many colorectal cancer-related procedures were suspended, with unclear implications for colorectal cancer mortality. In this study, van den Puttelaar and colleagues used observed data and simulation modeling to estimate the impact on colorectal cancer outcomes, clinical resources, and associated tradeoffs, for longer versus shorter recovery periods to catch up procedures. The authors estimate that the disruptions may cause 4,200 to 14,400 excess colorectal cancer deaths in the US in the next 20 years, depending on the assumed extent of disruption, length of recovery period, and resources used. These estimates may help inform strategies to mitigate the broader impact of the COVID-19 pandemic or future crises.Christopher and colleagues used a data-driven approach to identify exercise trajectories over the adult life course and examined how these trajectories were associated with colon cancer risk within the NIH-AARP Diet and Health Study. Adults maintaining moderate-to-high amounts of exercise consistently throughout adulthood had a lower risk of colon cancer. Being inactive early in adulthood but increasing exercise participation by midlife was also suggestive of a lower risk. These findings are aligned with the current physical activity recommendations and add new evidence that promoting physical activity at all stages of the adult life course is needed for population-based colon cancer prevention.Few empirical data are available for older adults on the absolute risk of colorectal cancer and its associated mortality in the context of prior screening. Dalmat and colleagues address this evidence gap with estimates from a large population of screen-eligible adults ages 76 to 85 years who had a negative colonoscopy ten years ago. Estimates of cumulative incidence and mortality were 1.29% (95% CI: 1.02–1.61%) and 0.46% (95% CI: 0.30–0.70%), respectively, in eight years following screening eligibility date, after accounting for competing risk of death from another cause. Patients were approximately 90 times more likely to die from another cause than colorectal cancer, which may be an important context for older adults’ decision making.Nicotine metabolism significantly influences nicotine dependence. The goal of this study, by Perez-Paramo and colleagues, was to examine the impact of genetic variants in nicotine metabolizing enzyme genes on urinary levels of nicotine metabolites. Functional deficiency of cytochrome P450 2A6 caused multiple changes in nicotine metabolites in smokers’ urine. Genetic polymorphisms in multiple functional metabolizing enzyme genes showed a significant impact on urinary levels of many nicotine metabolites. These data suggest that multiple genes in several pathways are involved in the metabolism of nicotine, which may influence nicotine dependence and smoking behavior.

Surgeons preference for lumbar disk surgery: a discrete choice experiment

PurposeMultiple surgical techniques are practiced to treat sciatica caused by lumbar disk herniation. It is unknown which factors surgeons find important when offering certain surgical techniques. The objective of this study is threefold: 1) determine the relative weight surgeons place on various characteristics of sciatica treatment, 2) determine the trade-offs surgeons make between these characteristics and 3) identify preference heterogeneity for sciatica treatment.MethodsA discrete choice experiment was conducted among members of two international neurosurgical organizations. Surgeons were asked on their preferences for surgical techniques using specific scenarios based on five characteristics: effectiveness on leg pain, risk of recurrent disk herniation, duration of postoperative back pain, risk of complications and recovery period.ResultsSix-hundred and forty-one questionnaires were filled in, the majority by neurosurgeons. All characteristics significantly influenced the preferences of the respondents. Overall, the risk of complications was the most important characteristic in the decision to opt-in or opt-out for surgery (35.7%). Risk of recurrent disk herniation (19.6%), effectiveness on leg pain (18.8%), postoperative back pain duration (13.5%) and length of recovery period (12.4%) followed. Four latent classes were identified, which was partly explained by the tenure of the surgeon. Surgeons were willing to trade-off 57.8% of effectiveness on leg pain to offer a treatment that has a 1% complication risk instead of 10%.ConclusionIn the context of this discrete choice experiment, it is shown that neurosurgeons consider the risk of complications as most important when a surgical technique is offered to treat sciatica, while the risk of recurrent disk herniation and effectiveness are also important factors. Neurosurgeons were prepared to trade off substantial amounts of effectiveness to achieve lower complication rates.

Minimally Invasive Surgical Techniques for Management of Painful Metastatic and Primary Spinal Tumors.

Patients with metastatic spinal disease are affected by disabling pain. The treatment of spinal metastases is focused on pain reduction and improvement in quality of life. Until recently, many patients with metastatic spinal disease did not qualify as surgical candidates due to the risks of surgery and length of recovery period. However, recent advances in minimally invasive surgery such as kyphoplasty and vertebroplasty allow patients to safely undergo surgery for pain relief with a short recovery period.The studies reviewed here suggest that vertebral augmentation is successful in reducing pain and disability scores in patients with painful metastases and multiple myeloma and are a safe modality to provide lasting pain relief. As the use of kyphoplasty and vertebroplasty for treatment of vertebral metastases is becoming more common, new combinations of cement augmentation with other techniques such as percutaneous pedicle screws and radiofrequency ablation are being explored. The implementation of kyphoplasty and vertebroplasty, in conjunction with other minimally invasive surgical techniques as well as nonsurgical modalities, may lead to the best palliative management of cancer patients with spinal metastases and help them ultimately achieve a better quality of life.

Evaluation of appropriateness of restoration period in professional activity in the case of physical and psychological and emotional stress in accordance with hormone status of the body

According to some hormones, a comparative evaluation of adequacy of recovery period in three groups of persons with different adaptation to physical loads and their severity was done. The authors found indices of hormonal status were within normal physiological standard during common everyday activity (students of institutes of higher education); it provided evidence about adequacy of night sleep period for recovery of human organism. High physical and psychoemotional loads led to significant changes in hypothalamo-pituitary-adrenal axis (sportsmen and students of military schools). The different levels of physical loads caused features in dynamics of some hormones and their associations. In sportsmen during periods of training and competition, the recovery period was inadequate for normalization of hormonal status of human organism; it provided evidence about inadequacy of the loads. During period of adaptation to conditions of organized collective, young students of military schools unadapted to physical and psychoemotional loads had higher expression of stress signs than sportsmen; length of recovery period was also inadequate. The catabolic processes in human organism prevailed over anabolic ones. The inadequate recovery of human organism is a risk factor for functional status and may lead to onset of pathological states.

Effect of Short Recovery Periods on Ocular Comfort During Daily Lens Wear.

To assess the impact of lens-free intervals of varying lengths on end-of-day comfort with soft contact lenses. Twenty-five symptomatic lens wearers participated in this randomized, cross-over study involving nine individual 12-hour days: one spectacle (no lens) and eight lens wear days. On each lens wear day, lenses were worn bilaterally in 2-hour intervals, separated by lens-free (recovery) periods of 0, 30, 60, or 80 minutes (repeated throughout the day). For each 2-hour lens wear interval, new lenses were worn. Ocular comfort was rated on a 0 to 100 visual analogue scale (0 = extremely uncomfortable); tear film and ocular parameters were assessed at the beginning and end of each study day. This study involved two different types of silicone hydrogel lenses, and the order of lens type and length of recovery period was randomized. Participants were unaware of the true study purpose and that a new lens pair was used for each lens wear interval. End-of-day comfort on lens wear days was significantly worse than on the spectacle day (p < 0.002). There was no significant effect of the recovery periods on end-of-day comfort (p > 0.05). Although lens wear affected noninvasive tear film break-up time and conjunctival staining, there were no effects of recovery period length on noninvasive tear film break-up time (p > 0.05), tear meniscus height (p > 0.05), corneal staining (p > 0.05), conjunctival staining (p > 0.05), bulbar conjunctival redness (p > 0.05), or limbal redness (p > 0.05). There was no consistent effect of recovery period length on lid margin staining. Lens-free recovery periods during a 12-hour lens wear day did not positively impact end-of-day comfort in this study. Cumulative lens wear times ranged from 8 to 12 hours, and the results suggest that once the length of lens wear exceeds the usual comfortable wear time, there is no benefit of short recovery periods.

A comparative study of four permanent cannulation procedures in rats

Introduction Permanent implantation of vascular catheters allows multiple blood sampling from the experimental animal. The aim of the study was firstly to establish four cannulation procedures in rats, which will result in high rate of catheter patency after the post surgical recovery period and secondly to determine a suitability of food and water consumption (FC and WC) and body weight gain (BW) as markers for the estimation of the length of recovery period. Methods Cannulation of the jugular vein ( n = 12), femoral vein ( n = 15), ileocolic vein ( n = 13) and the dual cannulation of the jugular vein/duodenum ( n = 7) were performed in the rat. Catheter patency was monitored throughout the recovery period. Rats were considered fully recovered after return of BW, FC and WC to the preoperative values. Results A decrease of catheter patency in the recovery period followed a linear regression model in all cannulation groups ( P < 0.01, R 2 > 0.87). BW significantly decreased in the rats subjected to ileocolic and jugular/duodenum cannulation procedures only. A significant transient decrease of FC and increase of WC was observed in all cannulation groups. FC returned to the preoperative values more slowly than BW and WC. Therefore FC was considered as the most sensitive parameter for the estimation of the length of recovery period, resulting in the recovery period of 10 days and catheter patency of 75–85% in the case of jugular vein, femoral vein and dual jugular vein/duodenum cannulation procedures. After the cannulation of the ileocolic vein FC did not return to the preoperative values. Discussion The catheter patency at the end of recovery period, which was estimated by the FC, was assured in the majority of rats in all cannulation groups, with the exception of the ileocolic vein cannulation group. In this particular cannulation group FC did not return to preoperative values, thus indicating that further optimization of the ileocolic vein cannulation procedure is required.

GS28P LAPAROSCOPIC CHOLECYSTECTOMY FOR OBESE PATIENTS

Background Laparoscopic surgery is often perceived to be more difficult for obese patients. Middlemore Hospital has unique patient population with high prevalence of obesity. This is a pilot study to compare the outcome of obese and non‐obese patients who had laparoscopic cholecystectomy in our institution. Our hypothesis is that obese patients do not suffer more adverse postoperative outcome.Methods We reviewed all patients undergoing acute and elective cholecystectomy from January 2004 to December 2006, 100 obese patients were identified. The control group consists of 100 non‐obese patients matched for age, sex and type of admission. Outcome assessed includes length of recovery period, complication and conversion rate.Results Over the three year period there were 1400 cholecystectomies, of which 96% were commenced laparoscopically. Overall conversion rate was 3.8%. The obese group has increased rate of wound complication (10% vs 2%, p = 0.037) and conversion rate (8% vs 3.5%, p = 0.28). The two study groups have similar median length of postoperative stay of 4 days.Conclusion This confirms our hypothesis that it is safe for obese patients to have laparoscopic cholecystectomy. However there is increased risk of conversion and wound complication.

Less Expensive Skin Resurfacing by Longer Pulse CO2 Laser

Resurfacing of the skin for eliminating defects like acne scars, wrinkles, keloids, etc. has traditionally been done by ultrapulse CO2 lasers in which there are very short pulses with high peak power in a repetitive fashion. The pulse duration may range from 0.1 to 200 per second with 1000 pulses per second. A short laser exposure with a high power density ablates the same volume of tissue as a longer exposure at a lower power. The high-power lasers are more expensive. A lower-power laser with longer pulse intervals provides a less expensive alternative. This paper describes the resurfacing results achieved with a lower-power and longer-pulse laser available at a fraction of the cost. The Luxar CO2 laser was used in pulse mode, with an exposure time of 20 milliseconds and a repetition rate of 20 times per second. The power level of 2–5 W pulse rate was evaluated on 69 patients using the following four metrics: (1) postoperative pain reported by the patient, (2) length of recovery period, (3) quality of achieved final result as measured by patient's satisfaction, and (4) complications. In each of these four regards the selected protocol was found to be very satisfactory and the results were comparable to those reported by the ultrapulse lasers.

Effect of time of application of MCPA and bromoxynil in relation to flowering on subterranean clover seed yield and quality

The importance of stage of phenological development and cultivar maturity ranking in influencing the seed yield response of subterranean clover (Trifolium subterraneum L.) to broadleaf herbicides was examined in a field study in southern New South Wales. The herbicides, bromoxynil (200 g a.i./L) at 1.4 L/ha and MCPA (500 g a.i./L) at 1.0 Wha, were applied 6 (TI) and 3 weeks (T2) before flowering, and at 5% flowering (T3) to 7 cultivars ranging from early to late flowering. The stage of phenological development at herbicide application, the maturity ranking of the cultivar and the herbicide applied, all influenced seed set. Application of bromoxynil at T1 did not reduce seed yield of any cultivar but increased seed yield of 4 cultivars by up to 30%. MCPA applied at the same time reduced seed yield in 1 cultivar by 26% and increased yields in 4 others by up to 57%. Application of bromoxynil at T3 caused reductions in seed yield in 3 of the 7 cultivars. MCPA applied at this time was more damaging than bromoxynil with all cultivars showing large seed yield reductions ranging from 22 to 64%. Despite large reductions in herbage yield as a result of some herbicide treatments, there was only a low correlation (r = 0.3, P&lt;0.01) between herbage yield at full flower and seed yield. Our findings suggest that the reduction in herbage yield and change in canopy structure as a result of the early application of herbicides stimulated seed production. Seed number was the primary yield component responsible for the change in seed yield with a high correlation (r = 0.86, P&lt;0.01) between these 2 parameters. Seed size was relatively insensitive to herbicide treatment but varied markedly with cultivar. Germination percentage of seed produced by swards treated with bromoxynil was unaffected, even when applied at T3, whereas MCPA lowered germination percentage of almost all cultivars if applied within 3 weeks of the commencement of flowering. The maturity ranking of the cultivars was highly negatively correlated with percentage seed yield loss (r = -0.80, P&lt;0.01) when either herbicide was applied at T3, the seed yield of the early flowering cultivars being most depressed by the herbicides. Length of recovery period between herbicide application and flowering was shown to be very important in influencing seed yield, the effect being modified by both herbicide and cultivar maturity.

Facial Cosmetic Surgery: A Primary Care Perspective

Primary care providers are often the source of information regarding health matters including elective cosmetic surgery. Practitioners should know about the more common cosmetic surgical procedures to assist their clients in making informed decisions regarding these operations. This article describes facial cosmetic surgical procedures performed to modify the signs of aging, which includes rhytidectomy ("face lift"), blepharoplasty ("eyelid surgery"), chemical peels, and dermabrasion. Issues discussed include preoperative considerations, expected outcomes, length of recovery period, costs, and complications (hemorrhage, necrosis, nerve injury, psychologic sequelae). Because facial cosmetic surgery usually has a positive impact on one's self-esteem, there has been an overall increase in facial cosmetic procedures during the past decade.

Mark-recapture experiments with noble crayfish, Astacus astacus L., in a Norwegian lake

. In July and August 1980–1987, mark-recapture experiments with noble crayfish, Astacus astacus L., were performed to estimate density in Lake Steinsfjorden, south-east Norway. Recapture rates were examined for variation according to sex, length, sampling method or length of recovery period, i.e. the time between release and recapture. Lake Steinsfjorden supports a dense, heavily exploited population of noble crayfish with few large individuals. Recapture rates did not vary with sex, but were significantly lower among crayfish smaller than 90mm total length than for larger crayfish. Different sampling methods (baited traps and scuba) prior to marking did not influence the rate of recapture (in baited traps). When the recovery period was increased from 2 to 4 days, the recapture rate increased two- to threefold, but a further increase in the recovery period to 4–6 days did not increase the recapture rate. The estimated density of noble crayfish varied between 013 and 036 individuals 5 70 mm total length per m2 (95% CL. varied from 84 to 280%).

Role of Exposure Duration in Hydrogen Ion Toxicity to Brook (Salvelinus fontinalis) and Rainbow Trout (Salmo gairdneri)

Acidification of streams and rivers associated with rainstorm or snowmelt events is often episodic as are many environmental introductions of toxic substances. We examined the toxicity of continuous or intermittent exposures to sulfuric acid (H+) to brook trout (Salvelinus fontinalis) embryos, alevins, and fry. Acute toxicity tests were conducted with juvenile rainbow trout (Salmo gairdneri). These studies permitted evaluation of key components of intermittent exposures (toxicant concentration, exposure duration, and recovery period) on mortality, reduced growth, and perturbed electrolyte balance. Lethality of H+ markedly changed with developmental stage of brook trout. Resistance of the chorion to H+ penetration probably protected embryonic fish, while hatching and onset of active swimming exacerbated H+ toxicity. Response surface methods demonstrated that between pH 4 and 7, time–concentration relationships for H+ toxicity were greatly influenced by exposure duration and peak concentration but little by length of recovery period. Daily pulses at pH 4 with duration as short 4.5 h produced marked mortality after 90 d. This did not occur after 4–60 d of testing. Whole-body Na+, K+, and Ca2+ concentrations of brook trout were negatively correlated with mean H+ concentrations after 90 d of exposure. Cation depletion appeared to be a more sensitive index of chronic, sublethal H+ toxicity than reduced growth.

Cervical mucus and oestrous behaviour responses to oestrogens in sheep: Progesterone-oestrogen relationships and role of progesterone pre-treatment

The final dose of progesterone (5, 10, 20 mg) and time to oestrogen injection relative to the final dose of progesterone (24–72 h) had no significant effect on the production of cervical mucus measured 24 h after the injection of 30 μg oestradiol benzoate (ODB). However, there were significant effects on the behavioural oestrous responses (time from injection of oestrogen to onset of oestrus and duration of oestrus). Time to onset of oestrus increased from 18 to 27.8 h with increasing dose of progesterone ( P < 0.001) and decreased from 24.8 to 20 h with increasing time to oestrogen injection ( P < 0.05). Conversely, the duration of oestrus decreased from 36.2 to 23.8 h with increasing dose of progesterone ( P < 0.001) and increased from 29 to 39 h with increasing time to oestrogen injection ( P < 0.01). Ovariectomized ewes became refractory to ODB as measured by the cervical mucus response after the fifth sequential daily injection of 20 μg oestradiol benzoate. Progesterone priming was not required to restore subsequent sensitivity to oestrogen treatment. However, there was a positive linear relationship between length of recovery period and level of response to subsequent treatment. It was concluded that: (1) progesterone pre-treatment or priming is not necessary in the cervical mucus bioassay in ovariectomized ewes; and (2) a period of 8–16 days is needed between assays for normal sensitivity to be regained.

Length of recovery period after surgical treatment of canine cervical intervertebral disc protrusion.

Length of recovery period after surgical treatment of canine cervical intervertebral disc protrusion.

Effect of time of cessation of wet season grazing on Townsville stylo-annual grass pasture at Katherine, N.T

A Townsville stylo (Stylosanthes humilis)-annual grass pasture at Katherine, N.T., was subjected to a series of treatments in 1969-70 and 1970-71 under which plots were grazed heavily from the beginning of the wet season for a period and then allowed to recover undefoliated for the remainder of the season. The dates at which heavy grazing ceased were spaced at 2-week intervals from November 24 to March 16. At the end of the wet season, total dry matter yield was linearly related to length of recovery period. Townsville stylo yield declined as recovery period was reduced from 18 to 8 weeks, but showed little response to a further reduction to 4 weeks. In contrast, annual grass yield showed little change as recovery period was reduced from 18 to 8 weeks, but fell with a further reduction to 4 weeks. As a result, the proportion of Townsville stylo in the pasture at the end of the season was high with long and short recovery periods but reached a minimum with an 8 - 10 week recovery period. Dry conditions prevailed in the first half of both seasons. The evidence suggests that young Townsville stylo is sensitive to heavy grazing when under water stress, and that early grazing for grass control should be imposed only during periods of active growth.

THE PRODUCTIVITY OF INTERMEDIATE WHEATGRASS AS AFFECTED BY INITIAL HARVEST DATES AND RECOVERY PERIODS

The productivity of Agropyron intermedium (Host.) Beauv., as influenced by variation in the date of initial harvest and length of recovery period between cuttings, was studied on irrigated land over a 2-year period. Ten initial cutting dates, each spaced 3 days apart, and two recovery periods of 21 days and 42 days, were used. Delaying the initial harvest date resulted in progressively greater dry-matter yields at the first cutting and progressively lower yields at the second cutting. Earlier and later initial cuttings gave higher yields than at the shotblade stage when this species seems to be in a critical phase of development. Grass given a 42-day recovery period between cuttings produced an average dry-matter yield of 3.63 tons per acre over the 2-year period, and 1.71 tons of root material per acre in the first crop year. Comparable yields in tons per acre for grass given a 21-day recovery period were 2.29 for dry matter and 1.31 for root material. Likewise, grass given a 21-day recovery period showed a rapid stand deterioration, whereas that given a 42-day recovery period did not show a reduction. Intermediate wheatgrass is high-yielding if managed properly and not abused by intensive cutting or grazing. It appears to be more suitable for hay production than for pasture.

Factors Controlling Color Change in the Tree Frog, Hyla versicolor Wiech

Hyla versicolor responds to light by melanophore expansion, and to darkness by contraction. The completenes of contraction depends upon duration of the period of dark-adaptation, generally more than 72 hours are required for all frogs to turn green. The change to brown after dark-adaptation is variable and no consistent relationship has been found between length of darkness and length of recovery period. Temperatures of 3-5° C darken frogs as does light. Light and cold appear to be stimuli which cause release of mel-anophorotropic hormone (ACTH?) from the pituitary gland. Light-induced changes, opposite to those shown by other frogs, seem explicable on the basis of natural selection during the diurnal period when these frogs are inactive.